I am no longer sure that a third-party AV program is essential, and some of them may be detrimental. Of course, needs vary. Some people are more accident-prone than others.
A putrid, nicotine-shaded mist loomed over Beijing on Thursday after a massive sandstorm slammed into the Chinese capital bringing the latest airpocalypse to this smog-choked city.
All these factors should be taken into account. A risk-aware Windows user can probably survive without any anti-virus software at all. I ran Windows XP for a year to try to prove it.