diff --git a/src/helpers/MQTTPresets.h b/src/helpers/MQTTPresets.h
index b5f342c8..1083026d 100644
--- a/src/helpers/MQTTPresets.h
+++ b/src/helpers/MQTTPresets.h
@@ -47,6 +47,24 @@ struct MQTTPresetDef {
 // Braces match topic placeholders ({device}/{iata}); never send this string to the broker.
 static const char MQTT_USERPASS_USERNAME_PUBKEY[] = "{pubkey}";
 
+// True when the broker tears down a live session once its JWT passes exp, so the
+// renewal must proactively bounce the connection to present a fresh token.
+//
+// Default true, because getting this wrong the safe way costs a re-handshake and
+// getting it wrong the unsafe way costs an outage. waev is the exception: its
+// operator confirmed (2026-08-11) that their servers do not disconnect on expiry,
+// so a live session there needs only its credentials refreshed for the next
+// reconnect. waev is also the only preset with a short token_lifetime, so it was
+// the only one bouncing often — every ~47 min, and each bounce's re-handshake can
+// cost ~10 KB of contiguous internal DRAM on a non-PSRAM board.
+//
+// Keyed by name rather than a struct field on purpose: adding a field would mean
+// re-ordering a dozen positional initialisers below, where a mistake is silent.
+static inline bool mqttPresetEnforcesTokenExp(const MQTTPresetDef* preset) {
+  if (!preset || !preset->name) return true;   // custom/audience slots: assume enforced
+  return strcmp(preset->name, "waev") != 0;
+}
+
 static inline bool mqttPresetUsesDevicePubkeyUsername(const MQTTPresetDef* preset) {
   return preset && preset->auth_type == MQTT_AUTH_USERPASS &&
          preset->userpass_username &&
diff --git a/src/helpers/bridges/MQTTBridge.cpp b/src/helpers/bridges/MQTTBridge.cpp
index d6dcc2b4..906f525a 100644
--- a/src/helpers/bridges/MQTTBridge.cpp
+++ b/src/helpers/bridges/MQTTBridge.cpp
@@ -2148,7 +2148,16 @@ void MQTTBridge::maintainSlotConnection(int index, unsigned long now_millis, uns
                                             (time_synced && old_token_expires_at >= 1000000000 &&
                                              current_time >= (old_token_expires_at - renewal_buffer));
 
-        if (old_token_expired_or_imminent || !slot.client->connected()) {
+        // Only bounce for exp if this broker actually enforces it. A broker that
+        // leaves live sessions alone past expiry needs the fresh token at the next
+        // reconnect, not now, and the bounce's re-handshake is where contiguity goes.
+        const bool exp_forces_bounce =
+            old_token_expired_or_imminent && mqttPresetEnforcesTokenExp(slot.preset);
+        if (!exp_forces_bounce && old_token_expired_or_imminent && slot.client->connected()) {
+          MQTT_DEBUG_PRINTLN("MQTT%d token renewed, no bounce (broker does not enforce exp)",
+              index + 1);
+        }
+        if (exp_forces_bounce || !slot.client->connected()) {
           // Disconnect + reconnect with fresh credentials, reusing existing client
           // to avoid internal heap leak/fragmentation from destroy/create cycles
           MQTT_DEBUG_PRINTLN("MQTT%d token renewal: reconnecting with fresh credentials", index + 1);