i'll be changing mine this spring. Almost to the 80hr mark and i always blow my leaves under my pine trees in the fall. My maples drop them late and it got cold fast last year and stayed, so I just removed battery treated gas tank and called it a season. I'd rather have changed fluids before storage, but winter seemed to come fast and stay. Anyway I was hoping to change it on a nice weekend in March, but considering it's still single digits right now, who knows when. just picked up the Hydro oil and filters off amazon. I don't plan on changing every season if fluids look ok, outside of engine oil.