Little harsh there, vlad.
When new, I would pay an LDS to assemble a reg set, and show me what to look for when I use it, such as inspection before and after diving.
I have taken an equipment class, but I still prefer to turn over regs and tanks to someone who is skilled and practiced in servicing them.
And service includes me walking in with a reg the guy hasn't sold me, isn't trained to work on, (and won't because of that), and yet will take the time to walk me through certain checks and such to troubleshoot a problem.
Service is taking the time after a class to video and point out to you some things of which you aren't aware. It's a form of mentorship -- but not everyone does it.