Modern operating systems (windows has done this particularly dramatically) have made a lot of efforts to incorporate most of the obvious wins of AV software dir

Modern operating systems (windows has done this particularly dramatically) have made a lot of efforts to incorporate most of the obvious wins of AV software directly into the OS. I think the only real thing of value is occasionally running system-wide scans - but serious infections are getting better at hiding themselves so you'll probably only find the cheaply written ad-spyware that way.