Not sure this is repeatable, but when we bought a home that needed a major rehab, what happened to us is we got a GC to bid the job, and then when it was 2x our budget we (first had a heart attack) then timidly asked if they could refer us to some roofers who could help us get the roof fixed before it rained, and this extremely kind person gave us their list of go-to subs, and as we saved up enough for that phase, we called them saying So and So gave us their number. (How we ended up short by half is a longer story.)