Keep in mind that every environment is unique and the frequency I list for these actions is based on the internal needs of the organization I work for and the scale of our deployment and the servers that host the system.
In my IEM Environment I do the following … (accomplished with Scheduled Tasks using the Command Line Utilities) …
Remove Duplicate Computers (Nightly)
Delete Non-Reporting Computers (not reporting after 90 days)
Purge Deleted Computers (deleted computers older than 180 days)
Delete Stopped/Expired Actions (older than 90 day)
In the SQL databases we do the following … (accomplished with Maintenance Plans in the SQL Server) …