You are not really buying a dishwasher. You are booking five handoffs: the measure, the haul, the hookup, the test, and the first week. The daughter who books it usually ends up catching whichever one gets dropped, so name who owns each one before the truck is on the street.

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.

Before the truck is booked

Measure the opening three ways: width at the front and back, height from the floor to the countertop edge, and depth from the front of the cabinet to the back wall or water line. Write those numbers next to the model number of the unit you want. Check the old unit for a label that gives its size, because a replacement that fits the cabinet opening is the difference between a clean swap and a return trip.

Look under the sink. Note the water shutoff, the drain connection, and whether the supply line is the flexible kind or stiff metal. Ask the installer in writing whether a new supply line and a new drain hose are included or billed separately.

Confirm the power source. Some dishwashers plug into an outlet under the counter, and some are hardwired. Find out which one your mother has, because a crew that arrives expecting the other will need a second visit.

The day of the install

Decide who lets the crew in and who signs the delivery ticket. If your mother is the only person home, a helper she trusts can receive the crew without making any decisions about the purchase. Write down where the key or entry code is kept so the whole family knows the route.

Ask who hauls the old unit away. Some crews take it, some leave it at the curb, and some charge for it. Get the answer on the paperwork, not from the driver. Ask the installer to walk the old hose and supply line out with you so you know what was removed.

Before the crew leaves, look at the floor under the new unit and the sink cabinet for any sign of water. Ask them to show you where the shutoff valve is and how to close it.

The first load

Run an empty cycle the same day, not the next week. Watch the drain, check the door seal, and look under the sink again after the cycle ends. Confirm the door latches and the racks slide smoothly.

Keep the manual, the warranty card, the installer's name, the store phone number, and the model and serial numbers in one labeled folder. When the machine stops working, the first call should go to the right number without a search.

Ask the installer one last question: what does a repair call look like for this brand in your area, who makes the call, and how long the wait usually runs. Write the answer into the folder with the paperwork.