Well I rely primarily on the "careful what you install" approach. I do actually have Avast! installed, but primarily for the phone location features. I do let it run an install-time scan, because that only takes a few seconds as a one-off, but don't otherwise run real-time scanning. I also have a copy of MalwareBytes installed, in case I want to run a manual scan (my experience of PC antivirus is that I get more false positives than real results, and hence like to have a couple of opinions available).
But AV vendors do have a habit of issuing "scare" reports whose purpose is to drive business, so I'm always a bit wary of those. I've found that a bit of care with what I install has sufficed so far.