The Bow Rehair - it's a crapshoot

I have to admit that I don't know too much about rehairing a bow. I know that I rarely plan for it...it usually gets to the point when I will be begging all shops in town to rehair my bow on short notice - unsuccessfully of course.

My last bow rehair was done on short notice. When it came back, I found the hair quite short. Gone was the little nudge between the frog and the thumb leather where my thumb rests when I play. The person who did my rehair was a well known luthier in town so I figured it was 'done right' and that it would probably stretch over time. It never stretched. Instead, my thumb kept pushing up on the thumb leather and eventually tore it....but I dealt with it.

Fast forward to last week...another rehair needed. I took it to another luthier..one who had rehaired 2 bows for me in the past. They were able to fit me in. When I saw them, I told them that the last rehair left the hair a bit too short for my tastes which was why the thumb leather was wearing out. I kinda made a big deal about it because I didn't want it to happen again. So...I paid for a rehair as well as money for the thumb leather to be replaced. I picked it up a couple of days later. Same thing! I sat down with them and asked them if that was the way it was supposed to be...and they said yes. I took it to my teacher...and he immediately said, too short. So I took it back and they corrected it.

How can they not know it's too short? Don't all these shops rehair bows all the time? I talked to a friend of mine and she has had bad experience with another shop in town. So basically, we have had bad rehairs from 3 shops now. Is it that difficult? I still consider myself a 'beginner' cellist so it's tough for me to tell the shops what I want with conviction because I'm not all that sure myself. I depend on them to tell me the 'right' way because I feel like they would know having done so many of them. However if my teacher can look at my bow and say, "Too short" but the shop is telling me it's fine...uhh...doesn't give me a warm and fuzzy feeling about who is working on my bow.

Any thoughts?