However, they are also all things you can do yourself in Windows, and for free. Avast Cleanup Premium will do all those things for you. There is a definite benefit to cleaning up old files, cleaning up your hard disks, removing old shortcuts, cleaning out old apps from your browser and deleting junk. Otherwise, if you use Windows 10 and have half-decent computer hygiene habits, you may not see a boost at all. If you have not maintained your PC for years and have been steadily installing and uninstalling apps during that time, you may get an initial performance boost.
The jury is still out on whether registry cleaners actually deliver any performance benefit or not.
