I do all my fluids, grease and air filter myself religiously. I also changed my belt at 100 hours just so I'd know how to do it when I needed to and put the original belt in my trail box.
I bought it new from 4 Wheels of Texas on N Beach. They no longer sell units but still have a very busy service operation. If you have a Ranger and need work and want it done by very experienced Polaris Certified Mechanics, you have to go see these people. The Tech's are grown men, like mid 40's and up with 20 or so years of experience. I took it in for plugs today, they did it while I waited as a favor to me. Took less than 1/2 hour and most of that time was cleaning the top of my engine to keep the panhandle from falling into my cylinders before they pulled the plugs. Greased them, properly torqued and gave me my original plugs as spares if I ever need them. They were that clean. It was running fine, I just thought that with 4600 miles it would need them. They charged me $52.00.

I knew I was running clean, I only use Shell fuel and try to fill up at the pump and not on the dirty trail. Also very careful with closing up the air filter box and keep that closure clean. My oil comes out pretty clean.