Well couple of things, higher rpm, slower speeds will make clutches and belt run hotter obviously. The other thing is the 1080 belts arent the best high temp belts. They are some of the softest rubber compound for Polaris sleds. If you arent blowing these out, your clutches cant be that hot. All the newer sleds have 1122 or 1115 belts because the 1080s couldnt handle the heat that is trapped in the newer hood and bellypan designs. Your clutches may be running hotter in the powder and hills, than they run on the trails, but it cant be that hot cuz the 1080s are surviving. Also the 1080 doesnt handle much slipping before it burns up or delaminates either, so I kinda doubt that is happening too.
I suspect your stuff is fine, but Im not there checking it out either. Its always a good idea to keep an eye on stuff, and go through everything and just inspect and make sure all is good, like rp7x is saying too.
BTW, 1080 belts are awesome belts performance wise, because they are soft, they also grip much harder than the newer belts. One reason why the Edge chassis sleds are so much easier to clutch than the newer sleds. They dont generally last as long as the 1115, but they are also half the price. Good luck