In addition to making sure databases are vacuumed regularly, it is worth
running REINDEX on tables that see a lot of updates (or insert/deletes).
Running REINDEX on a regular basis will keep the indexes compacted and
can noticeably improve the database performance.
The other benefit is that the disk space taken by your database can be
significantly reduced.
This is barely mentioned in the 7.4 docs, and alluded to in the 8.1 docs.
FWIW, in my experience it is DEFINITELY worth reindexing regularly.
John
