A reach-in can give you ten good years or five bad ones. Most of the difference is habit.

A cooler's compressor runs until the box reaches its set temperature, then rests. Anything that lets heat in, or keeps heat from getting out, makes it run longer.

A compressor that runs twice as long wears out sooner. Most of the habits below are free. They just have to happen every day, at every store.

The condenser pulls in room air to cool the refrigerant. If boxes, trash cans or supplies block the vents, the unit cooks in its own heat.

Keep the clearance the manual calls for, usually a few inches on the sides and back. Don't store anything on top of a unit with a top-mounted condenser.

The condenser coil collects dust, lint and grease from the kitchen air. A dirty coil can't shed heat, so the compressor runs hot and long.

Brush the outside of the coil monthly, with the power off. Have a technician clean it deep on a schedule. Kitchens near fryers and grills need it more often, because grease holds the dust.

The door gasket is the rubber seal around the door. Check all four sides for tears, cracks and flat spots.

Close the door on a dollar bill and pull it out. If it slides out with no drag, the seal is weak there. Try a few spots on each side. A worn gasket is a cheap part that saves a lot of power.

Wipe gaskets with warm, soapy water. Harsh cleaners dry them out and make them crack.

Keep the door closed. Every open minute lets warm, wet air in. Train the crew to grab what they need and close it. Fix a door that doesn't close on its own.

Keep the cabinet level. A cabinet that leans can keep the door from sealing, and can stop water from draining. Check the legs or casters when a unit gets moved.

Keep a log. Write the temperature down at the start and end of every shift. Cold food has to stay at 41°F or below. A unit that drifts up a degree a week is asking for a visit.