Back when you were renting an apartment, your landlord took care of maintenance issues like backed-up sinks and faulty water heaters — but now that you’re a homeowner, the responsibility for hiring contractors falls to you. Working only with officially licensed contractors protects you and your home from scams, overpricing and people who simply don’t know what they’re doing. Plumbers, electricians and any contractors performing a major service for you must be licensed by the state, and they must give you their license numbers upon request. Once you know a plumber’s number, checking his license status only takes minutes.