I've responded to similar threads before, but I'll put in my response here, too. I don't wear a full diaper when I ski, but always have some protection on; a size XL Goodnite fits me fine and is what I need for my issues. I am not incontinent, but do have an occasional issue with suddenly needing to pee while I am up on the mountain--and a long way to any restroom. Sometimes I don't make it to the restroom completely dry. The Goodnite is adequate for my needs--protection until I can get to the restroom and finish the job, so to speak. Although I can wet my Goodnite a fair amount in a day's time, I've never reached its capacity or had leaks. I don't get cold from the wetting, I'm comfortable, and I don't need to change before the end of my ski day.
The other folks' comments here are very insightful and worth noting. Just decide and know what your limits for your diaper/wetting will be and don't push beyond that point.