While it's never a bad idea to take a more active, informed role in protecting yourself from malware, my suggestion does not need a whole lot of ongoing maintenance.
And yes, most folks in the know use a multiple level defense strategy, though I personally think running multiple pieces of overlapping software is not as good an approach as more passive means. But modern computers are VERY powerful, and the case could be made that the power is there to help protect you.
One other point: Besides Avast being installed I personally would not use and have never used an automatic "cleaner" tool. I don't trust some other programmer to know which bits of my data are safe to delete - they CAN'T know. However, I have deep operating system knowledge and I *do* use other tools such as Autoruns to help me manually maintain my system, because there *is* a need for maintenance. I understand that not everyone has the same knowledge about how to keep a system running smoothly.
-Noel