There are lots of ways to fix a wayward, crash-prone Android, whether you're watching your processes or very carefully managing tasks. But sometimes things just seem generally, generically busted. That's when it's time to give your phone the factory reset.
Tech site Tested writes an informative piece on all the things you can do to avoid running your phone through a factory reset, but eventually comes around to noting that, through dumb luck, it's occasionally unavoidable. That's when it's time to make sure your backup and app data settings are in order and run through the re-install process. It's explained in some detail at the post, and is worth a good read-through if you're wondering if your Android phone really used to be much faster and responsive.