Mac: No matter how neat you are, we all suffer from desktop clutter: those icons you drag there for quick access and forget to clean until they've taken over your entire screen. Free app Clean will tidy up your desktop regularly without you having to lift a finger.
While you could always set up a more complicated filing system with something like Hazel, Clean is a simple app that takes just a few clicks to set up. It serves one simple purpose: keeping your Desktop from overflowing with icons. You can set it to clean it daily or weekly, as well as choose how you want to organise items (like shuffle them into sub-folders labelled by month). It's no substitute for actually going through those items every once in a while, and it won't exactly work if you use your desktop as a to-do list, but it'll keep you from going insane with clutter until you're ready to dig into those items and organise them yourself.
Clean is a free download for Mac only.