From what i've noticed, most people are fine with it exactly the way it is set right after installing.
It's more or less the "safest" at the point of install, but there are a lot of other things that you can set, which, even after years of using it, I don't do. I've tried other settings, but mostly just use it as an easy way to get rid of temp files and history.
I only ever use the file cleaning part of it now. The registry cleaning part is debatable, registry cleaners in general are not a good thing to use or fool around with. Most people will urge you not to use one. The CCleaner reg cleaner is also set initially so it only gets rid of the obvious entries, but messing with the registry isn't safe if you don't know what you're doing. I used it a lot on my desktop and never ever had an issue. I haven't used it on my laptop yet because i'm paranoid.
So, all in all, I basically leave it as is after install, and let it do it's thing. It's not "all powerful", but it does the lightwork instead of having to delete browsing history, cache, emptying the recycle bin, and getting rid of old log files.
