Congratulations on your purchase. May you have many years of good service out of it.
I have a 2004 RTV900W with 2,650 hours on it. I added a canopy top, work lights and a fiberglass bed liner (bed liner was a mistake), when I bought it. It uses no oil between engine oil changes and drives like new.
It gets used a minimum of twice a day doing chores at the barn, and frequently more often since it's so useful for moving people and tools around to do things like clear up fallen trees, etc.
I installed the one piece front drive shaft kit, which newer ones won't need. Replaced the front CV joint boots and all associated seals ~four years ago. Rebuilt the bed after the horse manure corroded it and much of the rest of the bed. Replaced the tail gate. I should have had Rhinoliner, or equivalent installed when I bought it.
Replaced the front struts @ ~2,500 hours.
Other than that, just routine maintenance and an occasional light bulb in the work lights.
Edited to add: Performance of routine maintenance is relatively easy on this machine. Oil changes on the front differential are less easy because of the way mud and other stuff packs between it and the skid plate. But other than that, much easier than a modern car. Good access to all the stuff done often, like oil changes.
I expect to have to rebuild the U-joints in the rear axles before it gets to 3,000 hours, but everything else is working just fine. (Knocking on wood here.)
Fitch