If 'cleaners' are not snake oil then what do they remove from registry that measurably improves performance? What were the symptoms of broken PCs, what did they do/not do after being repaired by programs which removed registry entries?
CCleaner has a nice /AUTO switch to clean your web browsing history/cache/recycle bin, but allowing anything to blindly remove registry entries it sees fit is risky business.
Original poster, you probably noticed how your Windows runs smooth and fast after initial install? Partition your hard drive and install Windows onto a relatively small partition. Perhaps install different versions of Windows on different partitions. Perhaps install large programs/games on their own partitions. As long as you don't keep personal data on the OS partitions, you can image/reimage one OS from the other in a few minutes and have things running exactly as they did at the time you made the image.
You can defrag your mechanical hard drive once in a while, but SSDs are so inexpensive now that it makes a lot of sense to install Windows on a SSD drive which does not need to be defragmented ever and gives you a real increase in performance you can feel.