I use one, but never really thought about it much. Therefor I'm with Avira (free version) for over a decade now. Recently I got fed up with those pop-up windows prompting me to upgrade for paid version.
I dont have much critical information or useful things on my computer so security is not my top priority. I found most anti virus just gets in the way
Windows defender does an alright job, and dosent get in the way. As long as your smart about where you go and what you download I would say your probably ok, depending on how critical your security is.