Always wear a helmet when I ride ATV. When we started using the Gator UTV a year ago, we did both wear helmets the first few times we went. Always wear seatbelts to of course, but now we have stopped the helmets. I figure there is a full roll cage, so if I am belted in I am probably OK, unless I get hit by a bigger vehicle. Then, so be it.
ONE COOL THING we started doing however, is using a 2-place intercomm and low cost aviation headsets, when traveling on the road with the UTV. Its cuts the wind, allows you to converse without yelling, and reduces noise of course. also, its cool to be able to talk at a low volume so people can't hear what you are saying. Last time I checked, headsets were available for under $50 each, and intercomms cost about twice that.