In general, you won't need to mess with any other tabs in the CacheFu control panel other than Main. The default cache policy, although a bit conservative, will work just fine in most cases.
However, depending on your use case, you may find that you can get away with making CacheFu more aggressive. You may also find that you need to tweak the cache settings to accommodate add-on products that create new content types, which the default policy doesn't know how to cache.
Thankfully, CacheFu makes it easy to tinker with the cache settings without messing up the default configuration. So you can always revert if you don't like the results.
In most cases, rather than create a new policy from scratch, it ...