There are good and bad contractors that make trades, etc look bad. My worst experience was with a painter about 15 years ago. Had too many jobs on the go, there was a different person at our place every day that did not seem to really know where the last one had left off. Tried to tell me that walls had two coats and it was clear they had only one. I have not hired one since but I know there are good ones out there.
In the petrochemical industry we deal with quality co troll and sign offs.
I've now done that with any contractor I hire. I benefit from being in construction and also knowing all the crafts and what needs to be done. I do most my work myself but when a job is too big I will hire someone but I lay out a sign off inspection form for each part of the work.
If I'm laying good money I demand it be done right.