CCleaner is a must, especially if you fail to clean various browser caches. I back up its registry cleaner with Glary Utilites and then run the Glary registry defrag. I was a devoted fan of Defraggler, but the latest release has issues with the app's service continuing to run after use and then it sits there using up resources until it cause a system bog down or crash. So I have switch to IObit's Smart Defrag v2. Be sure to use the Boot Time Defrag to get the system files defragged.