This is a sensible routine for a small board. Adjust it to your traffic.
Every night
Run PBUtil FC after downloads, so that file counters and the top-download lists stay current.
Run PBUtil DM (daily maintenance).
If you use FidoNet mail, toss and scan mail on a schedule. See FidoNet mail.
Rotate the logs with Tools > Rotate Logs Now, or from the Log Viewer's Clear. See Logs.
You can start any of these from a Windows scheduled task, or from an event in PBEVENTS.CFG, which PBDispatch runs. See Program updates for an example of an event.
Every week or month
PBUtil MP packs message bases and removes deleted messages. Run it with no callers online.
PBUtil UP packs the user file.
PBUtil UK removes users who have never come back, if you want to.
Check Reporting for failed logins and ban lists, and run Tools > Login Guard > Clear Bans only if good addresses were caught.