diff --git a/crates/brk_server/src/api/mempool_space/addrs.rs b/crates/brk_server/src/api/mempool_space/addrs.rs
index f227123ac..499ae5f18 100644
--- a/crates/brk_server/src/api/mempool_space/addrs.rs
+++ b/crates/brk_server/src/api/mempool_space/addrs.rs
@@ -30,7 +30,7 @@ impl AddrRoutes for ApiRouter<AppState> {
                 Path(path): Path<AddrParam>,
                 State(state): State<AppState>
             | {
-                let strategy = state.addr_cache(Version::ONE, &path.addr);
+                let strategy = state.addr_cache(Version::ONE, &path.addr, false);
                 state.cached_json(&headers, strategy, &uri, move |q| q.addr(path.addr)).await
             }, |op| op
                 .id("get_address")
@@ -53,7 +53,7 @@ impl AddrRoutes for ApiRouter<AppState> {
                 Query(params): Query<AddrTxidsParam>,
                 State(state): State<AppState>
             | {
-                let strategy = state.addr_cache(Version::ONE, &path.addr);
+                let strategy = state.addr_cache(Version::ONE, &path.addr, false);
                 state.cached_json(&headers, strategy, &uri, move |q| q.addr_txs(path.addr, params.after_txid, 50)).await
             }, |op| op
                 .id("get_address_txs")
@@ -76,7 +76,7 @@ impl AddrRoutes for ApiRouter<AppState> {
                 Query(params): Query<AddrTxidsParam>,
                 State(state): State<AppState>
             | {
-                let strategy = state.addr_cache(Version::ONE, &path.addr);
+                let strategy = state.addr_cache(Version::ONE, &path.addr, true);
                 state.cached_json(&headers, strategy, &uri, move |q| q.addr_txs(path.addr, params.after_txid, 25)).await
             }, |op| op
                 .id("get_address_confirmed_txs")
@@ -119,7 +119,7 @@ impl AddrRoutes for ApiRouter<AppState> {
                 Path(path): Path<AddrParam>,
                 State(state): State<AppState>
             | {
-                let strategy = state.addr_cache(Version::ONE, &path.addr);
+                let strategy = state.addr_cache(Version::ONE, &path.addr, false);
                 state.cached_json(&headers, strategy, &uri, move |q| q.addr_utxos(path.addr)).await
             }, |op| op
                 .id("get_address_utxos")
diff --git a/crates/brk_server/src/api/mempool_space/blocks.rs b/crates/brk_server/src/api/mempool_space/blocks.rs
index ee7660053..193eab65e 100644
--- a/crates/brk_server/src/api/mempool_space/blocks.rs
+++ b/crates/brk_server/src/api/mempool_space/blocks.rs
@@ -117,7 +117,7 @@ impl BlockRoutes for ApiRouter<AppState> {
                            headers: HeaderMap,
                            Path(path): Path<TimestampParam>,
                            State(state): State<AppState>| {
-                        state.cached_json(&headers, CacheStrategy::Tip, &uri, move |q| q.block_by_timestamp(path.timestamp)).await
+                        state.cached_json(&headers, state.timestamp_cache(Version::ONE, path.timestamp), &uri, move |q| q.block_by_timestamp(path.timestamp)).await
                     },
                     |op| {
                         op.id("get_block_by_timestamp")
diff --git a/crates/brk_server/src/api/mempool_space/general.rs b/crates/brk_server/src/api/mempool_space/general.rs
index 982ef66da..30fea0901 100644
--- a/crates/brk_server/src/api/mempool_space/general.rs
+++ b/crates/brk_server/src/api/mempool_space/general.rs
@@ -3,7 +3,7 @@ use axum::{
     extract::{Query, State},
     http::{HeaderMap, Uri},
 };
-use brk_types::{DifficultyAdjustment, HistoricalPrice, Prices, Timestamp};
+use brk_types::{DifficultyAdjustment, HistoricalPrice, Prices, Timestamp, Version};
 
 use crate::{
     AppState, CacheStrategy, extended::TransformResponseExtended, params::OptionalTimestampParam,
@@ -66,8 +66,12 @@ impl GeneralRoutes for ApiRouter<AppState> {
                        headers: HeaderMap,
                        Query(params): Query<OptionalTimestampParam>,
                        State(state): State<AppState>| {
+                    let strategy = params
+                        .timestamp
+                        .map(|ts| state.timestamp_cache(Version::ONE, ts))
+                        .unwrap_or(CacheStrategy::Tip);
                     state
-                        .cached_json(&headers, CacheStrategy::Tip, &uri, move |q| {
+                        .cached_json(&headers, strategy, &uri, move |q| {
                             q.historical_price(params.timestamp)
                         })
                         .await
diff --git a/crates/brk_server/src/api/mempool_space/mining.rs b/crates/brk_server/src/api/mempool_space/mining.rs
index 44c476f83..2c8fc2869 100644
--- a/crates/brk_server/src/api/mempool_space/mining.rs
+++ b/crates/brk_server/src/api/mempool_space/mining.rs
@@ -8,7 +8,7 @@ use axum::{
 use brk_types::{
     BlockFeeRatesEntry, BlockFeesEntry, BlockInfoV1, BlockRewardsEntry, BlockSizesWeights,
     DifficultyAdjustmentEntry, HashrateSummary, PoolDetail, PoolHashrateEntry, PoolInfo,
-    PoolsSummary, RewardStats,
+    PoolsSummary, RewardStats, Version,
 };
 
 use crate::{
@@ -154,7 +154,7 @@ impl MiningRoutes for ApiRouter<AppState> {
             "/api/v1/mining/pool/{slug}/blocks/{height}",
             get_with(
                 async |uri: Uri, headers: HeaderMap, Path(PoolSlugAndHeightParam {slug, height}): Path<PoolSlugAndHeightParam>, State(state): State<AppState>| {
-                    state.cached_json(&headers, CacheStrategy::Tip, &uri, move |q| q.pool_blocks(slug, Some(height))).await
+                    state.cached_json(&headers, state.height_cache(Version::ONE, height), &uri, move |q| q.pool_blocks(slug, Some(height))).await
                 },
                 |op| {
                     op.id("get_pool_blocks_from")
diff --git a/crates/brk_server/src/api/mempool_space/transactions.rs b/crates/brk_server/src/api/mempool_space/transactions.rs
index 099ddeb87..4ad215eae 100644
--- a/crates/brk_server/src/api/mempool_space/transactions.rs
+++ b/crates/brk_server/src/api/mempool_space/transactions.rs
@@ -10,7 +10,8 @@ use brk_types::{CpfpInfo, MerkleProof, Transaction, TxOutspend, TxStatus, Txid,
 
 use crate::{
     AppState, CacheStrategy,
-    extended::TransformResponseExtended,
+    cache::CacheParams,
+    extended::{ResponseExtended, TransformResponseExtended},
     params::{TxidParam, TxidVout, TxidsParam},
 };
 
@@ -132,7 +133,16 @@ impl TxRoutes for ApiRouter<AppState> {
                     Path(path): Path<TxidVout>,
                     State(state): State<AppState>
                 | {
-                    state.cached_json(&headers, CacheStrategy::Tip, &uri, move |q| q.outspend(&path.txid, path.vout)).await
+                    let v = Version::ONE;
+                    let immutable = CacheParams::immutable(v);
+                    if immutable.matches_etag(&headers) {
+                        return ResponseExtended::new_not_modified_with(&immutable);
+                    }
+                    let outspend = state.run(move |q| q.outspend(&path.txid, path.vout)).await;
+                    let height = state.sync(|q| q.height());
+                    let is_deep = outspend.as_ref().is_ok_and(|o| o.is_deeply_spent(height));
+                    let strategy = if is_deep { CacheStrategy::Immutable(v) } else { CacheStrategy::Tip };
+                    state.cached_json(&headers, strategy, &uri, move |_| outspend).await
                 },
                 |op| op
                     .id("get_tx_outspend")
@@ -157,7 +167,16 @@ impl TxRoutes for ApiRouter<AppState> {
                     Path(param): Path<TxidParam>,
                     State(state): State<AppState>
                 | {
-                    state.cached_json(&headers, CacheStrategy::Tip, &uri, move |q| q.outspends(&param.txid)).await
+                    let v = Version::ONE;
+                    let immutable = CacheParams::immutable(v);
+                    if immutable.matches_etag(&headers) {
+                        return ResponseExtended::new_not_modified_with(&immutable);
+                    }
+                    let outspends = state.run(move |q| q.outspends(&param.txid)).await;
+                    let height = state.sync(|q| q.height());
+                    let all_deep = outspends.as_ref().is_ok_and(|os| os.iter().all(|o| o.is_deeply_spent(height)));
+                    let strategy = if all_deep { CacheStrategy::Immutable(v) } else { CacheStrategy::Tip };
+                    state.cached_json(&headers, strategy, &uri, move |_| outspends).await
                 },
                 |op| op
                     .id("get_tx_outspends")
@@ -237,7 +256,8 @@ impl TxRoutes for ApiRouter<AppState> {
             post_with(
                 async |State(state): State<AppState>, body: String| {
                     let hex = body.trim().to_string();
-                    state.sync(|q| q.broadcast_transaction(&hex))
+                    state.run(move |q| q.broadcast_transaction(&hex))
+                        .await
                         .map(|txid| txid.to_string())
                         .map_err(crate::Error::from)
                 },
diff --git a/crates/brk_server/src/api/mod.rs b/crates/brk_server/src/api/mod.rs
index 9b1ac9834..8f9637c18 100644
--- a/crates/brk_server/src/api/mod.rs
+++ b/crates/brk_server/src/api/mod.rs
@@ -6,7 +6,7 @@ use aide::{
 };
 use axum::{
     Extension,
-    http::{HeaderMap, header},
+    http::HeaderMap,
     response::{Html, Redirect, Response},
     routing::get,
 };
@@ -78,13 +78,12 @@ impl ApiRoutes for ApiRouter<AppState> {
             )
             .route("/api", get(Html::from(include_str!("./scalar.html"))))
             // Pre-compressed with: brotli -c -q 11 scalar.js > scalar.js.br
-            .route("/scalar.js", get(|| async {
-                (
-                    [
-                        (header::CONTENT_TYPE, "application/javascript"),
-                        (header::CONTENT_ENCODING, "br"),
-                    ],
+            .route("/scalar.js", get(|headers: HeaderMap| async move {
+                Response::static_bytes(
+                    &headers,
                     include_bytes!("./scalar.js.br").as_slice(),
+                    "application/javascript",
+                    "br",
                 )
             }))
             .route(
diff --git a/crates/brk_server/src/api/series/bulk.rs b/crates/brk_server/src/api/series/bulk.rs
index 8cbf9a380..65bc82598 100644
--- a/crates/brk_server/src/api/series/bulk.rs
+++ b/crates/brk_server/src/api/series/bulk.rs
@@ -4,15 +4,15 @@ use axum::{
     Extension,
     body::{Body, Bytes},
     extract::{Query, State},
-    http::{HeaderMap, StatusCode, Uri},
-    response::{IntoResponse, Response},
+    http::{HeaderMap, Uri},
+    response::Response,
 };
 use brk_types::{Format, Output, SeriesSelection};
 
 use crate::{
     Result,
     api::series::{CACHE_CONTROL, max_weight},
-    extended::{ContentEncoding, HeaderMapExtended},
+    extended::{ContentEncoding, HeaderMapExtended, ResponseExtended},
 };
 
 use super::AppState;
@@ -34,7 +34,7 @@ pub async fn handler(
     let csv_filename = resolved.csv_filename();
 
     if headers.has_etag(etag.as_str()) {
-        return Ok((StatusCode::NOT_MODIFIED, "").into_response());
+        return Ok(Response::new_not_modified(&etag, CACHE_CONTROL));
     }
 
     // Phase 2: Format (expensive, server-side cached)
diff --git a/crates/brk_server/src/api/series/data.rs b/crates/brk_server/src/api/series/data.rs
index cdcf25e05..533642b3a 100644
--- a/crates/brk_server/src/api/series/data.rs
+++ b/crates/brk_server/src/api/series/data.rs
@@ -4,8 +4,8 @@ use axum::{
     Extension,
     body::{Body, Bytes},
     extract::{Query, State},
-    http::{HeaderMap, StatusCode, Uri},
-    response::{IntoResponse, Response},
+    http::{HeaderMap, Uri},
+    response::Response,
 };
 use brk_error::Result as BrkResult;
 use brk_query::{Query as BrkQuery, ResolvedQuery};
@@ -14,7 +14,7 @@ use brk_types::{Format, Output, SeriesOutput, SeriesSelection};
 use crate::{
     Result,
     api::series::{CACHE_CONTROL, max_weight},
-    extended::{ContentEncoding, HeaderMapExtended},
+    extended::{ContentEncoding, HeaderMapExtended, ResponseExtended},
 };
 
 use super::AppState;
@@ -57,7 +57,7 @@ async fn format_and_respond(
     let csv_filename = resolved.csv_filename();
 
     if headers.has_etag(etag.as_str()) {
-        return Ok((StatusCode::NOT_MODIFIED, "").into_response());
+        return Ok(Response::new_not_modified(&etag, CACHE_CONTROL));
     }
 
     // Phase 2: Format (expensive, server-side cached)
diff --git a/crates/brk_server/src/api/series/legacy.rs b/crates/brk_server/src/api/series/legacy.rs
index 8f973b7a9..82eaa4683 100644
--- a/crates/brk_server/src/api/series/legacy.rs
+++ b/crates/brk_server/src/api/series/legacy.rs
@@ -4,15 +4,15 @@ use axum::{
     Extension,
     body::{Body, Bytes},
     extract::{Query, State},
-    http::{HeaderMap, StatusCode, Uri},
-    response::{IntoResponse, Response},
+    http::{HeaderMap, Uri},
+    response::Response,
 };
 use brk_types::{Format, OutputLegacy, SeriesSelection};
 
 use crate::{
     Result,
     api::series::{CACHE_CONTROL, max_weight},
-    extended::{ContentEncoding, HeaderMapExtended},
+    extended::{ContentEncoding, HeaderMapExtended, ResponseExtended},
 };
 
 pub const SUNSET: &str = "2027-01-01T00:00:00Z";
@@ -36,7 +36,7 @@ pub async fn handler(
     let csv_filename = resolved.csv_filename();
 
     if headers.has_etag(etag.as_str()) {
-        return Ok((StatusCode::NOT_MODIFIED, "").into_response());
+        return Ok(Response::new_not_modified(&etag, CACHE_CONTROL));
     }
 
     // Phase 2: Format (expensive, server-side cached)
diff --git a/crates/brk_server/src/cache.rs b/crates/brk_server/src/cache.rs
index eef737553..c4b96323b 100644
--- a/crates/brk_server/src/cache.rs
+++ b/crates/brk_server/src/cache.rs
@@ -33,6 +33,13 @@ pub struct CacheParams {
 }
 
 impl CacheParams {
+    pub fn immutable(version: Version) -> Self {
+        Self {
+            etag: Some(format!("i{version}")),
+            cache_control: "public, max-age=1, must-revalidate".into(),
+        }
+    }
+
     /// Cache params using CARGO_PKG_VERSION as etag (for openapi.json etc.)
     pub fn static_version() -> Self {
         Self {
diff --git a/crates/brk_server/src/extended/header_map.rs b/crates/brk_server/src/extended/header_map.rs
index 69d6cc0e8..67898ee22 100644
--- a/crates/brk_server/src/extended/header_map.rs
+++ b/crates/brk_server/src/extended/header_map.rs
@@ -19,6 +19,8 @@ pub trait HeaderMapExtended {
     fn insert_content_type_application_json(&mut self);
     fn insert_content_type_text_csv(&mut self);
 
+    fn insert_vary_accept_encoding(&mut self);
+
     fn insert_deprecation(&mut self, sunset: &'static str);
 }
 
@@ -59,6 +61,7 @@ impl HeaderMapExtended for HeaderMap {
     fn insert_content_encoding(&mut self, encoding: ContentEncoding) {
         if let Some(value) = encoding.header_value() {
             self.insert(header::CONTENT_ENCODING, value);
+            self.insert_vary_accept_encoding();
         }
     }
 
@@ -70,6 +73,10 @@ impl HeaderMapExtended for HeaderMap {
         self.insert(header::CONTENT_TYPE, "text/csv".parse().unwrap());
     }
 
+    fn insert_vary_accept_encoding(&mut self) {
+        self.insert(header::VARY, "Accept-Encoding".parse().unwrap());
+    }
+
     fn insert_deprecation(&mut self, sunset: &'static str) {
         self.insert("Deprecation", "true".parse().unwrap());
         self.insert("Sunset", sunset.parse().unwrap());
diff --git a/crates/brk_server/src/extended/response.rs b/crates/brk_server/src/extended/response.rs
index a38f98493..82b2635c4 100644
--- a/crates/brk_server/src/extended/response.rs
+++ b/crates/brk_server/src/extended/response.rs
@@ -1,8 +1,9 @@
 use axum::{
     body::Body,
-    http::{HeaderMap, Response, StatusCode},
+    http::{HeaderMap, Response, StatusCode, header},
     response::IntoResponse,
 };
+use brk_types::Etag;
 use serde::Serialize;
 
 use super::header_map::HeaderMapExtended;
@@ -12,22 +13,36 @@ pub trait ResponseExtended
 where
     Self: Sized,
 {
-    fn new_not_modified() -> Self;
+    fn new_not_modified(etag: &Etag, cache_control: &str) -> Self;
+    fn new_not_modified_with(params: &CacheParams) -> Self;
     fn new_json_cached<T>(value: T, params: &CacheParams) -> Self
     where
         T: Serialize;
     fn static_json<T>(headers: &HeaderMap, value: T) -> Self
     where
         T: Serialize;
+    fn static_bytes(
+        headers: &HeaderMap,
+        bytes: &'static [u8],
+        content_type: &'static str,
+        content_encoding: &'static str,
+    ) -> Self;
 }
 
 impl ResponseExtended for Response<Body> {
-    fn new_not_modified() -> Response<Body> {
+    fn new_not_modified(etag: &Etag, cache_control: &str) -> Response<Body> {
         let mut response = (StatusCode::NOT_MODIFIED, "").into_response();
-        let _headers = response.headers_mut();
+        let headers = response.headers_mut();
+        headers.insert_etag(etag.as_str());
+        headers.insert_cache_control(cache_control);
         response
     }
 
+    fn new_not_modified_with(params: &CacheParams) -> Response<Body> {
+        let etag = Etag::from(params.etag_str());
+        Self::new_not_modified(&etag, &params.cache_control)
+    }
+
     fn new_json_cached<T>(value: T, params: &CacheParams) -> Self
     where
         T: Serialize,
@@ -49,8 +64,29 @@ impl ResponseExtended for Response<Body> {
     {
         let params = CacheParams::static_version();
         if params.matches_etag(headers) {
-            return Self::new_not_modified();
+            return Self::new_not_modified_with(&params);
         }
         Self::new_json_cached(value, &params)
     }
+
+    fn static_bytes(
+        headers: &HeaderMap,
+        bytes: &'static [u8],
+        content_type: &'static str,
+        content_encoding: &'static str,
+    ) -> Self {
+        let params = CacheParams::static_version();
+        if params.matches_etag(headers) {
+            return Self::new_not_modified_with(&params);
+        }
+        let mut response = Response::new(Body::from(bytes));
+        let h = response.headers_mut();
+        h.insert(header::CONTENT_TYPE, content_type.parse().unwrap());
+        h.insert(header::CONTENT_ENCODING, content_encoding.parse().unwrap());
+        h.insert_cache_control(&params.cache_control);
+        if let Some(etag) = &params.etag {
+            h.insert_etag(etag);
+        }
+        response
+    }
 }
diff --git a/crates/brk_server/src/lib.rs b/crates/brk_server/src/lib.rs
index 8d3cb26c0..3b07e7d4a 100644
--- a/crates/brk_server/src/lib.rs
+++ b/crates/brk_server/src/lib.rs
@@ -4,7 +4,10 @@ use std::{
     any::Any,
     net::SocketAddr,
     path::PathBuf,
-    sync::Arc,
+    sync::{
+        Arc,
+        atomic::AtomicU64,
+    },
     time::{Duration, Instant},
 };
 
@@ -59,6 +62,7 @@ impl Server {
             data_path,
             website,
             cache: Arc::new(Cache::new(1_000)),
+            last_tip: Arc::new(AtomicU64::new(0)),
             started_at: jiff::Timestamp::now(),
             started_instant: Instant::now(),
         })
diff --git a/crates/brk_server/src/state.rs b/crates/brk_server/src/state.rs
index 621349613..3a32ed901 100644
--- a/crates/brk_server/src/state.rs
+++ b/crates/brk_server/src/state.rs
@@ -1,7 +1,10 @@
 use std::{
     future::Future,
     path::PathBuf,
-    sync::Arc,
+    sync::{
+        Arc,
+        atomic::{AtomicU64, Ordering},
+    },
     time::{Duration, Instant},
 };
 
@@ -10,7 +13,10 @@ use axum::{
     http::{HeaderMap, HeaderValue, Response, Uri, header},
 };
 use brk_query::AsyncQuery;
-use brk_types::{Addr, BlockHash, BlockHashPrefix, Height, Txid, Version};
+use brk_types::{
+    Addr, BlockHash, BlockHashPrefix, Height, ONE_HOUR_IN_SEC, Timestamp as BrkTimestamp, Txid,
+    Version,
+};
 use derive_more::Deref;
 use jiff::Timestamp;
 use quick_cache::sync::{Cache, GuardResult};
@@ -28,6 +34,7 @@ pub struct AppState {
     pub data_path: PathBuf,
     pub website: Website,
     pub cache: Arc<Cache<String, Bytes>>,
+    pub last_tip: Arc<AtomicU64>,
     pub started_at: Timestamp,
     pub started_instant: Instant,
 }
@@ -43,15 +50,26 @@ impl AppState {
         }
     }
 
-    /// Smart address caching: checks mempool activity first, then on-chain.
+    /// `Immutable` if timestamp is >6 hours old (block definitely >6 deep), `Tip` otherwise.
+    pub fn timestamp_cache(&self, version: Version, timestamp: BrkTimestamp) -> CacheStrategy {
+        if (*BrkTimestamp::now()).saturating_sub(*timestamp) > 6 * ONE_HOUR_IN_SEC {
+            CacheStrategy::Immutable(version)
+        } else {
+            CacheStrategy::Tip
+        }
+    }
+
+    /// Smart address caching: checks mempool activity first (unless `chain_only`), then on-chain.
     /// - Address has mempool txs → `MempoolHash(addr_specific_hash)`
     /// - No mempool, has on-chain activity → `BlockBound(last_activity_block)`
     /// - Unknown address → `Tip`
-    pub fn addr_cache(&self, version: Version, addr: &Addr) -> CacheStrategy {
+    pub fn addr_cache(&self, version: Version, addr: &Addr, chain_only: bool) -> CacheStrategy {
         self.sync(|q| {
-            let mempool_hash = q.addr_mempool_hash(addr);
-            if mempool_hash != 0 {
-                return CacheStrategy::MempoolHash(mempool_hash);
+            if !chain_only {
+                let mempool_hash = q.addr_mempool_hash(addr);
+                if mempool_hash != 0 {
+                    return CacheStrategy::MempoolHash(mempool_hash);
+                }
             }
             q.addr_last_activity_height(addr)
                 .and_then(|h| {
@@ -125,9 +143,13 @@ impl AppState {
         F: FnOnce(&brk_query::Query, ContentEncoding) -> brk_error::Result<Bytes> + Send + 'static,
     {
         let encoding = ContentEncoding::negotiate(headers);
-        let params = CacheParams::resolve(&strategy, || self.sync(|q| q.tip_hash_prefix()));
+        let tip = self.sync(|q| q.tip_hash_prefix());
+        if self.last_tip.swap(*tip, Ordering::Relaxed) != *tip {
+            self.cache.clear();
+        }
+        let params = CacheParams::resolve(&strategy, || tip);
         if params.matches_etag(headers) {
-            return ResponseExtended::new_not_modified();
+            return ResponseExtended::new_not_modified_with(&params);
         }
 
         let full_key = format!("{}-{}-{}", uri, params.etag_str(), encoding.as_str());
diff --git a/crates/brk_types/src/txout_spend.rs b/crates/brk_types/src/txout_spend.rs
index aa1eb2303..3f608fbb8 100644
--- a/crates/brk_types/src/txout_spend.rs
+++ b/crates/brk_types/src/txout_spend.rs
@@ -1,7 +1,7 @@
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 
-use crate::{TxStatus, Txid, Vin};
+use crate::{Height, TxStatus, Txid, Vin};
 
 /// Status of an output indicating whether it has been spent
 #[derive(Debug, Clone, Serialize, Deserialize, JsonSchema)]
@@ -29,4 +29,13 @@ impl TxOutspend {
         vin: None,
         status: None,
     };
+
+    pub fn is_deeply_spent(&self, current_height: Height) -> bool {
+        self.spent
+            && self
+                .status
+                .as_ref()
+                .and_then(|s| s.block_height)
+                .is_some_and(|h| (*current_height).saturating_sub(*h) > 6)
+    }
 }