docs: add suggested default 12h for IPNS Entry TTL

src/ipns/ipns-record.md

@@ -3,7 +3,7 @@ title: IPNS Record and Protocol
 description: >
   Specifies the IPNS protocol in a language-agnostic manner, allowing everyone to
   create a compatible IPNS Record Publisher or Resolver.
-date: 2023-07-24
+date: 2023-10-03
 maturity: reliable
 editors:
   - name: Vasco Santos
@@ -151,9 +151,9 @@ A logical :dfn[IPNS Record] is a data structure containing the following fields:
   - Implementations MUST include this value in inside the DAG-CBOR document at `IpnsEntry.data[Sequence]`.
 
 - **TTL** (uint64)
-  - A hint for how long the record should be cached before going back to, for instance the DHT, in order to check if it has been updated.
+  - A hint for how long (in nanoseconds) the record should be cached before going back to, for instance the DHT, in order to check if it has been updated.
   - Implementations MUST include this value inside the DAG-CBOR document at `IpnsEntry.data[TTL]`.
-
+  - Suggested default: 12 hours (43 200 000 000 000 nanoseconds).
 - **Public Key** (bytes)
   - Public key used to sign this record.
     - If public key is small enough to fit in IPNS name (e.g., Ed25519 keys inlined using `identity` multihash), `IpnsEntry.pubKey` field is redundant and MAY be skipped to save space.