The best thing you can do, if you are at all mechanically minded, is to do it yourself.
It's not a space shuttle, it's just a record player, and there is nothing in it which is complicated or hidden. With a little research and care it's pretty easy to take care of a turntable yourself. Dealers want you to think it's a black art, I can't think why..., but you've got to think about the reality of the situation for a few minutes.
In the shop you will have, if you're lucky, the owner or other senior staffer who knows how to fettle a turntable. Great, but do you think the shop owner wants to spend all day in the back room with his head over a workbench? No. he wants to swan around like he, well, owns the place. Good chance you'll find a spotty youth in the back room prodding at your deck in a clueless daze. Exaggeration? Truth, I've seen it with my own eyes when I took my LP12 to a Linn dealer for 'service'. What he did to it I don't know but it sounded exactly the same when I got it back.
But don't they have clever bods who know about electrics and stuff? Yes, sometimes, but turntables are simple so you can let the chimps do them!
After another trip to the same Linn dealer for a 'service' I got home to discover that the packing between the inner platter and the top-plate had not been put in when the deck was boxed up. This is a major no-no as it meant the bearing spindle was bouncing against the bottom of the bearing well all the way home in the boot of my car. Yip, kid about seventeen had done it, a different one.
And can you assume that if you get a grown-up you're in safe hands? Well let's think about that now. Kid's at school, good at tech, good at maths, good head for all things practical. So he could maybe become an engineer or work in a Hi-Fi shop! Think about it, if you were technically minded at all and had half a brain would you even consider working in a shop?
Back in time again, I was getting fed up with my not very brilliant sounding LP12 so asking around on Hi-Fi forums I was advised that a certain dealer in Edinburgh was 's*** hot' with turntables. Not a Linn dealer but knew his stuff so off I went. Another fifty-quid lighter I found myself with a turntable that sounded worse than it had to begin with! Very hard and edgy with little bass.
Totally hacked off by this time I bought an LP12 service manual, talked to a few people and looked up everything else I could find about setting the deck up. When I started on the deck I found that the muppet in Edinburgh had tightened up all the fasteners like a gorilla on drugs! The bolt that holds the arm pillar in place was so tight it took my full weight on it to free it, what a bang it made when it snapped free. Do you remember that a lot of Linn Akito tonearms were ruined because the arm pillar had been crushed by the locking bolt? Well that's why. They had been fitting by idiots, probably working in Linn dealers, who had a wonky understanding of the term 'Linn-tight'. My arm was an Ittok so it was fine but I'd just paid another chunk of cash to some guy who knew less about mechanics than I do.
So honestly, if you are at all mechanically minded just do some homework and stake a claim on the kitchen table for a few hours. If you take your time and don't go mental on the fasteners it's very unlikely you'll do any harm. Over time you'll hear what differences certain changes make and soon you'll be able to set up your deck like a pro. Sorry, better than a pro! ;0)