My suggestion is that the best tool for this job is you (not that you are a tool).
But really -- most of those cleanup or check programs are just snake oil.
You can do a better job by just pressing Ctrl-Shift-Escape and checking your Startup tab to make sure nothing extra is auto-starting. And run the command "cleanmgr" if you want to clean up old temporary files (they won't slow down your PC, but they can
use extra space you might want to clean up).
Aside from that, a modern operating system built in the past several years already does a great job of maintaining itself. Unless you have a problem, just use your computer normally.
Here's some links with useful info too: Fix a Sluggish or Slow PC without a hassle
and
Quickly Repair PC Problems without buying anything