I would say they would need at least five years of experience. They would of course need a contractor’s license and make sure they’re classified in glazing. You always want to check their quality of work, as well, and another tip would be to see how they handle communication. If they don’t answer their phone the first time you call, that’s a red flag. We’re currently working on a house in Pasadena, a complete remodel, and the homeowner wanted 5 references from us from our past work. We communicated well, we were very transparent, and she ultimately signed us to begin remodeling her home.