I wear both always. I can't imagine rolling without a cup, and in fact, I'm not sure I would do a tournament where they are illegal. I would much rather tap because some guy is driving his cup into my back than get my own nuts smashed. I can see how that stuff might matter to serious people, but I just compete for fun and I would rather be able to keep my junk safe, even if it means someone might use a cup to their advantage. I've seen so many people get hit in the nuts during training that it almost seems suicidal not to wear a cup.