When buying a used RZR….

I am really wanting to buy a new 4 seater 900, but the price of new is a bit steep after taxes and upgrades. So my question is, what would be considered a high hours/high mileage RZR? Be it 2 seater of 4 seater. What is the longevity of the engines and suspension for these SxS’s. I do realize that the previous owners maintenance and driving habits will factor in to my question.
Thanks for your time and input.