Older buildings, newer appliances
Half of Manhattan's homes were built by 1951, and almost half of Brooklyn's date from before 1940, by the Census Bureau's latest five-year survey. A new dishwasher can end up draining into much older plumbing, so the tech checks the drain hookup and the outlet as well as the machine.
Laundry in a closet
Stacked washer-dryers and ventless dryers are common in apartments where there's no outside wall to vent through. A ventless dryer that won't finish usually has a clogged condenser or a lint path packed tight, not a dead heater. Say if yours is stacked: the top unit may have to come down.
Gas ranges and the city's rule
In New York City, work on gas piping and gas appliance hookups has to be done by a Licensed Master Plumber or someone qualified working under one. If the range smells of gas, leave the apartment and call 911 once you're outside. The oven and range page covers what an appliance tech handles and what needs the plumber.
Soft water, different wear
The city's tap water averages about 2 grains per gallon, soft by any standard, so scale is rarely what's clogging an ice maker or dishwasher here. That points the tech toward filters, food soil, pumps and door seals first.