What condenser coils actually do
Your refrigerator doesn't make cold — it moves heat. The compressor pumps refrigerant through condenser coils (usually under or behind the cabinet), and those coils dump the heat it just collected from inside the fridge into your kitchen air.
When a blanket of dust and pet hair coats the coils, that heat can't escape. The compressor runs longer and hotter to compensate. Heat is what kills compressors, and a compressor is the single most expensive component in the machine.
How often to clean them
Once a year is the baseline for most homes. If you have shedding pets, a dusty street, or the fridge sits in an enclosed nook, twice a year is safer. Built-in and integrated units with tight clearances deserve the more frequent schedule.
The tell-tale signs you're overdue: the fridge runs constantly, the sides or back feel hot to the touch, the kitchen seems warmer near the fridge, or your energy bill creeps up without a new appliance to blame.
Doing it yourself (safely)
Unplug the fridge first — always. Coil fans can start without warning.
Pull the machine out or remove the bottom rear grille. On most models the coils are visible as a black finned grid. Use a long, narrow coil brush (hardware stores carry them) and a vacuum with a crevice tool. Work in the direction of the fins, gently — bent fins restrict airflow just like dust does.
Don't use water or cleaners on the coils. Compressed air blows the dust into the room and into the compressor compartment — the brush-and-vacuum method keeps it contained.
When to call a pro
If the fridge still runs warm after a proper coil clean, the fault has moved past maintenance — evaporator fans, defrost systems, start relays, and thermostats all mimic a dirty coil. That's a diagnostic job, and guessing at it costs more than measuring it.
Built-in units and integrated columns are also worth professional service: accessing the coils usually means removing trim panels, and a cracked panel costs far more than the service call.
In the Langford job mentioned above, the visit included the coil clean, a full cooling-system check, and a factory reset to spec — cooling restored, running quiet, no new fridge needed.