I personally think the first oil change is more important than the rest, as if anything was in there from the factory build, the sooner you get it out the better
after that, I base my oil changes on HOW hard I use the atv or not, and how my oil looks when I check it BEFORE I use it!
if its DARK black, its due for a change! IMO
oil today, even TOP shelf oil, is still WAY cheaper than a new motor, or motor work
I change my oil more often than most, but in 35+ yrs of running motor's never had one blow up or fail on me , that didn't have a TON of wear and yrs on them!