High-end jobs mean costly materials and sophisticated designs, and finding and keeping “golden” subs is critical. The other end of the spectrum means job delays, warranty work, and strained customer relations. “A careless plumber can cause a lot of expensive destruction in very little time,” says Alex Dahlgren, partner at Acheron Construction in Garland, Texas. “One wrong turn of the wrench can ruin a $700 faucet.”