There is a not often recognized trick also...in 'most' cases, if you hold down 'shift' when you delete something, it bypasses the recycling bin....This is especially useful when deleting a large batch of files at the same time using a file manager.

Also, a lot of stuff can build up in certain temporary folders.

see this guide, or try This program

You can also get an extra external drive to save stuff to....and no matter what, you should have **SOME** way to backup your comouter in case of a crash.