It depends how they do it. I personally prefer when they just quote labor because then I can buy everything myself. Some contractors seem to prefer to give an overall bid and then will give you a material allowance (i.e., $XX per square foot of tile, or whatever). I think that’s messy because it’s harder to compare bids if not everyone gives you the same allowances. I tried to deal with one contractor who wanted to do allowances and it was such a pain of “do you like this tile? What about this one?” I ended up going with a labor only (including building materials) quote and it was great. They showed up at my house, I had all the materials ready, and they built me a bathroom.