How-ToInstall or Remodel

Most “simple swap” surprises trace back to the purchase, not the plumber. A few checks before you buy keep installation day boring — which is what you want.
The fixture is often fine — it’s the fifty-year-old shutoff valve under the sink that won’t close, or the corroded flange under the toilet, that turns a swap into a repair. A pro checks these first and fixes them while everything is already apart, which is exactly when it’s cheapest.
Swapping a faucet with good shutoffs is a reasonable DIY job. Anything involving the gas line, the drain in the wall, a shower valve, or a toilet flange that doesn’t look right is where a licensed plumber earns their fee — water damage from a small mistake costs far more than the install.
Measure before you buy, and budget for the possibility that what’s behind the fixture needs attention too. That’s the whole secret.