Rule #1 ... oops sorry that one is already taken.
Rule #2 nobody touches my gear.
The only exception to Rule #2 for me is the technician at the dive shop. I envy MikeF and others who are able to work on their own gear.
The nice thing about ScubaPro is that parts are free for life.
If you have found a good dive shop, then they do all their work on-site and nothing gets "sent out" except tank hydros.
$75 is typical for repair of a regulator. When you get the parts bill in addition, you may wish you had bought ScubaPro.