CVT's......especially the Polaris CVT's (and the Kawasaki Mule V-twins)....
The belt does not last long when the machine is used as a "tractor", or anything that pulls from a dead stop. Even though you may have a 2000 lb capacity, you'll want to be in LOW gear with that load. Low gear takes some of the load off of the belt. Sure, they're cheaper, but for a reason.
I've never replaced a belt on a Yamaha Ultramatic or a Kubota RTV. Not one. But the Kubota's are all HST's and don't have a belt
The Yamaha does have a belt, but they use a completely different design, such that the belt doesn't slip, ever (unless it's completely submerged in water). Actually the Yamaha's Ultramatic is SO good that Kawasaki copied it with the Teryx 4 750 and all the 800's. Polaris and Kawasaki Mule's both use a traditional CVT, which means that every time you're sitting still in gear, the drive converter is wearing against the belt. Then when you go to take off, the drive converter shifts in against the belt to put tension on it. It is at that point when the most wear occurs, which is every time you take off. The more load against it, the more it wears.
https://www.youtube.com/watch?v=YcHVsjwrp1M
Good vid of how it all works, and it's 100% accurate. I work on all types and the Polaris, Kawasaki, Arctic crap, John Deere I keep belts in stock for...but since I've never seen a Yamaha belt worn out, I have never seen the need to replace one. I've got a well used Rhino 700 with 19,800 miles on the original belt if that tells you anything.