By the way, the Routine Vacuuming chapter of the documentation says:
"The sole disadvantage of increasing autovacuum_freeze_max_age (and vacuum_freeze_table_age along with it) is that the pg_xact and pg_commit_ts subdirectories of the database cluster will take more space
[...]
If [pg_xact and pg_commit_ts taking 0.5 and 20 GB, respectively] is trivial compared to your total database size, setting autovacuum_freeze_max_age to its maximum allowed value is recommended."
Maybe this should be qualified with "unless you have trouble with your autovacuum keeping up" or so; or generally reworded?
This recommendation is in the mindset of "wraparound never happens".
If your database is large, you have more chances to hit it painfully, and if it's append-only even more so.
Alternative point of "if your database is super large and actively written, you may want to set autovacuum_freeze_max_age to even smaller values so that autovacuum load is more evenly spread over time" may be needed.
