Denis Gervalle's dashboard

In the book, the chapter regarding scheduled task is really descriptive, but it missed typical sample of what it is good to do ?
Should we periodically clear caches of mirrored repositories ? How often it is typically good to evict useless items ? should reindexing and attribute rebuilt regularly ? Should snapshots be treated differently than release ?
It would be nice to have some suggestion for a typical repository, proxying the central repository and storing corporate poms in hosted repositories.

I do not really understand if clearing caches, reindexing, rebuilding of attribute are required task for properly proxy the maven repository and host our own project ?