Mom's kitchen faucet has started to weep at the base, or the sprayer hangs like it has given up, and you have a Saturday that is partly yours. This is a job you can finish in one afternoon if you walk it in order. Nobody needs to be a plumber. You need a bucket, a towel, a flashlight, and about an hour before you need to be anywhere else.
Local option: New Plan Care gives families in the St. Louis area in-home help so a parent can stay home: companionship, help with bathing and dressing, meals, and overnight care. Call (314) 405-0887.
Step one: count the holes before you shop
Look at the sink deck. A single-hole faucet sits in one opening. A center set covers three holes in a line. Some sinks have an extra side hole that the new faucet may not use. The new faucet has to match the deck you already have, or you will be buying a cover plate or making a second trip. Write down the hole count, the spacing between holes, and whether the old faucet sits on a plate. A phone photo from under the sink is worth more than your memory.
Step two: find the shutoff valves and test them
Under the sink you should see two small valves, one for hot and one for cold, each with a flexible line running up to the faucet. Turn them clockwise to close. Then run the faucet. If water still comes out, the valves are not holding, and that is a plumber's call before anything else, because the rest of the job depends on the water being off. If the valves are stiff or never fully shut, do not force them. Note it on your list and ask for help.
Step three: buy for the sink you have
Check the supply lines. Many new faucets come with their own, but if you reuse the old ones, look at the ends. Ask the store whether the supply line fittings match what is on the valves. Replace the drain assembly too if the old one is cracked or leaks. Keep the receipt and the box until the first drip test has passed.
Step four: take the old one out without a fight
Close the valves, open the faucet to release the pressure, and set the bucket under the work area. Disconnect the supply lines at the valves first. The mounting nuts underneath can be older than your car and stuck tight. Spray a penetrating oil, wait a few minutes, and use a basin wrench if you have one. If a nut will not move, stop and take a photo of how it sits before you try anything else. A faucet that is loose in its hole is one you can lift out with patience.
Step five: set the new one, then test slowly
Seat the new gasket where the manufacturer's instructions show it. Lower the faucet, hand-tighten the mounting nuts from underneath, then snug them. Connect the supply lines hand-tight, then give each a small turn with a wrench. Open the valves slowly. Turn the faucet on at low pressure and check every joint under the sink with a dry paper towel. Run hot, then cold, then both, for several minutes. Check again an hour later.
What to watch for in the first week
Look under the sink the next morning. A paper towel that stays dry is the good answer. If you find a drip, tighten that joint a quarter turn and check again. A drip that keeps coming back usually means the connection is wrong, not the faucet. Keep the manual in a drawer where the family can find it, and write the valve locations on the inside of the cabinet door so the next person knows where to turn.
Where the help fits
Mom's afternoon helper is good company for this job. A non-medical helper can hold the flashlight, keep the bucket out of the way, and hand you tools in order. The work itself stays with the family, and a licensed plumber handles a bad valve or a cracked drain. If that happens, you will hand the plumber a clean list, because you did the counting and the photos first.