This is a can of worms that has opinions on both sides.
Personally, I don't use antivirus regularly on android. A good rule of thumb is simply to not be stupid. As long as you're only downloading play store apps from reputable developers and aren't going to the deep dark parts of the internet you're more than likely not going to run into any problem.
Android is similar to windows in this regard. I just use Microsoft's built in antivirus, run an anti-malware scan every couple of months just to be sure, and haven't had a piece of malware on a windows computer in over 4 years. Have never had anything on Android. Being smart with your usage habits will remove 95% of the risk. it is actually really hard to get malware on a computer (of which Android is a type of) now, and usually requires direct user interaction to make it happen.
Others will disagree with me and insist you run an antivirus on your device, but I personally don't think it is needed.