Mama always said, "A little knowledge is dangerous."
One reason I always liked to do my own mech work was that I always ended up with a better understanding of how the thing actually worked. This led to better anticipation of what was going to need the next bit of attention or faster diagnosis if something did break.
The second reason was that every high-priced wrench I've ever employed never cleaned a ****ed thing. WhenI do my own, it takes a long time, but half of that time is spent cleaning every bit I can reach.
Good luck.