Having bodged and fixed bikes since the age of about six I find it incomprehensible that anybody would want to trust their pride and joy and their own safety to a so-called professional but I guess I just have to accept that there are some people who either don't want to or haven't got it.
There's a passage in Zen and the Art of Motorcycle Maintenance where the author describes taking a motorbike that's had a seizure and as a consequence has got piston slap to his local repair shop. The mechanic is listening to loud pop music and has a casual, don't care attitude. He listens to the engine and says "Yeah... Tappets" then proceeds to try to remove the tappet cover with the wrong spanner, damaging the cover in the process. Realises he's messed up so goes off to get a small chisel and a hammer to beat the cover round. Pirsig watches in horror as the guy takes a swing at the chisel, misses and hits the engine, chipping a cooling fin. He takes the bike away and decides he'd rather live with a sloppy piston than suffer further damage at the hands of this idiot.
I'm sure most bike shop mechanics are NOT like this but it illustrates the "don't care" attitude that you sometimes find in so-called professionals. I reckon car dealers are worse for this.
Anyway... "annual servicing"? A bike should be serviced according to the use it gets, not following a schedule. A mountain bike used in Lancashire grit will need a lot more servicing than a road bike used on dry roads only, the MTB will probably need some attention every couple of rides and more if the rider is mechanically un-sympathetic.