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There is no one value fits all or we'd be using that and not giving you any options.

The session optimiser frequency depends on your traffic. If you have several thousand unique visitors per day you may want to run every 1 to 4 hours. If you have a few hundred visitors a day once a day is fine. If you have less than that you could go even less frequent. Even that option is not strictly necessary if your site is using InnoDB tables for the session. The session optimiser dates back to when Joomla was always using a MyISAM table to store session data. MyISAM is susceptible to fragmentation and table corruption which is why this feature exist.

The cache and temp directory cleaning are normally not necessary. We only include them for sites which have some problem or another or use an extension which abuses either folder to store web accessible files instead of the media folder, as it should be doing.

To put it very simply, most modern Joomla 3 sites can do away with these features. If you do not observe any difference just disable all three of them.

You're welcome!