If you fix your own equipment, even an expensive one is cheap compared to paying a mechanic and service truck to show up.

I have parts manuals for all my equipment. Still lacking the service manual for my MT Cat though. It is expensive ($800 ±) and new enough where I haven't seen them turn up on eBay. Dealer is good about photo-copying pages of interest for what we're tending to at the time, but there is still a manual in my future.

My son is a decent hand with a wrench and he doesn't work on stuff unless he has a manual. That serves to motivate me a LOT.