It can be hard to grasp, coming from a Windows environment, but Android/Linux has its own routines to manage RAM and temp files and cache. Unlike in Windows, Android/Linux benefits from having stuff sitting in RAM, and it does not hurt performance like you think. The most RAM cleaning you need to do can be accomplished from the Recent Apps screen by clicking the clear all button. All that 'good use' you're getting out of it is really just making the phone work harder.
That being said, I have SD Maid, but I use it very sparingly, mostly in cleaning up app caches and stuff before making a backup, or if I've uninstalled a bunch of apps, I use it to check to leftover bits and tombstones.
Android/Linux is extremely efficient at what it does...be a stable and effective operating system that requires very little user maintenance.