Bathroom single-hole, kitchen pull-down, or widespread—calculate the full replacement cost including shut-off valves, supply lines, drain assembly, and labor so your faucet quote covers every connection under the sink.
A corroded angle stop that's been in place for 15 years will fail when you turn it. Sometimes it fails while the customer is watching you, flooding the cabinet. Sometimes it fails two weeks later when they go on vacation. Either way, it's your callback. Always recommend replacing the shut-off valves when you're replacing the faucet—labor is already on-site, and a new quarter-turn ball valve costs $12. The conversation: "While I'm in here, I'd like to replace these shut-offs—they're original to the house and I'd rather do it now than come back for an emergency." Almost no one says no.
When a customer supplies their own fixture, they've usually bought a cheap one online, missing pieces, wrong configuration, or incompatible connections. You open the box, find a problem, and now you're either making a supply house run on their time or telling them the job can't happen today. Charge a "customer-supplied fixture fee" (typically $25–$50) to cover the extra time when things don't go perfectly. Or better: sell them a fixture with a full markup—you make margin and control the installation quality.
Under a 30-year-old sink, the supply lines are braided steel that's fused to the shutoffs, the packing nut won't budge, and the basket strainer is cemented in with plumber's putty and mineral deposits. What should be a 45-minute job becomes 2.5 hours. Always assess access difficulty at the time of estimate—or build an "if connections are corroded, add $X" clause into the quote. Document what you find when you open the cabinet.
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Get the Plumber's Kit →Faucet replacement pricing depends on faucet type, access, whether shut-offs need replacing, and how old the supply lines are. This calculator accounts for all of it: faucet and parts markup, labor time by access difficulty, shut-off and supply line work. Use it to stop charging the same flat rate for a simple kitchen swap and a difficult under-sink installation in a cabinet with corroded shut-offs.