It goes both ways. I'm sitting here tonight working ona student flute that was returned to me five weeks after originally repairing it. The customer was miffed that "they paid a lot of money for this flute and a lot of money to get it serviced and it doesn't play."
The customer is always right.
They did pay too much for this flute, a student model Suzuki. if they paid any more than $20 they paid too much. One of the advertised features of this flute is that it's designed so that kids can't bugger it up.
Horse Apples! What this translates to, is "we've made the adjustment screws as inaccessible as possible to truly give your repair tech the s#!%s.
The metal is very soft and the damn things struggle to hold any adjustments. When I serviced the flute (at the discount student rate of $100 for a full strip down, clean regulate replace necessary pads, corks, etc and replace head cork, polish, yada, yada), I play tested and magnehelic tested it. All good. The flute comes back to me with all different key heights, keys bent, and damaged adjustment screws. The kids teacher says the flute played very well for a student flute when the kid got back from me.
Long story short, the kid has buggered the flute and to avoid bad press (mum whingeing to every other mum at the school) I'm basically doing a full overhaul on a crap flute for free.
So, expect good work from your tech but remember,most of the problems found on any instrument are a result of operator eror in one form or another and more often than not, your tech has done way more work than you paid him for.