At what! I have heard and seen about experienced what ever. An induvial or a one man shop can get it to 80% with effort. Then other 20% gets lost in the day to day operations.
An expensed induvial or shop can get it to 99% real quick. The other 1% has to worked out. Unexposed or unforeseen problems come up. No parts, wrong parts, bad parts. Personal shortage, vacation illness, family. Garage burns! Seen that happen! Garage blows up!
Seen that Too! ( Short story. Knew a guy had a garage. Got to know him while I was working at a machine shop. His brother would help from time to time. They both had OLD'S 442 W30. One yellow and one orange. So I stopped in one day and walker in the door. At the back of the shop on the right the was a lot of block laying around. ? He was also a block layer. I ask. Are you expanding your shop? He said we are now! He explained they were changing changing a gas tank K 5 Blazer and couldn't get the gas out for some reason. So they poked a hole and drained it. Any how the gas got spilled or something to that effect. Don't quite remember. They did open the doors right away. The phone rang and set off the fumes and expanded the garage!

I did call him mid week to let him know his head was ready. But no answer.

That's why I stopped in.
By chance Bill did fix a 1/4 on a car the wife wiped out! My fault because I showed her a short cut home from work. Back road crossing a T intersection one road came down the hill and made a hump. I showed and told her you have to slow down or the hump will put you into the guardrails. Well guess what, it happened. I looked at it and said there's $800 damage! Got the easement from Bill and it was $810. Here again she said I was wrong.
The point here Bill gave me a day to bring it in and said. I have all the parts. It will be done by the end of the week I have 1 or 2 to do ahead of you depending on there parts.
Mid week he called me and said it's done. I was perfect! You couldn't even tell where it was touched! I know what I'm looking for!
A good shop big, little or very small can give a sound answer and or make way to get it done close to the estiment.
Bottom line: A professional knows there next move!
I have to give a plug to @
cawley
I have seen his work on this site.