Air conditioning is a winter system too
In a state with real winters, air conditioning reads as a summer luxury, which is why it gets ignored for nine months and then fails in the week it is wanted.
The part most drivers do not know: on the majority of vehicles, the air conditioning compressor runs when the defroster is on. The system dries the air before it reaches the glass, which is what clears a fogged windshield quickly rather than slowly.
A vehicle with no working air conditioning is therefore a vehicle that defrosts worse, in the season when seeing out of the windshield is not optional. That is the practical reason to deal with it rather than live with it.
What usually goes wrong
Air conditioning is a sealed system, and the common fault is that it is no longer sealed. Refrigerant escapes slowly through a seal, a hose or a fitting, and performance drops off gradually enough that people adjust to it.
Other causes exist: a failed compressor, a blocked condenser, an electrical fault, a clogged cabin filter that reduces airflow rather than cooling. Working out which is which is what the service is for.
Why topping it up is not a repair
The refrigerant did not evaporate. It went somewhere, through a leak, and a recharge that does not find the leak buys a season and no more.
A proper service finds the loss, fixes it, then restores the system to the correct charge. An overcharged system cools worse than a correct one, which is a thing that surprises people who assume more is better.
Say something at a service visit
The useful habit is to run the air conditioning for a few minutes every month, winter included, which keeps the seals lubricated and the system exercised.
The second is to mention any change when the vehicle is in for something else. Cooling that is noticeably weaker, a smell when it is switched on, or a noise from the compressor is worth looking at during a visit you were making anyway. See scheduled maintenance and oil changes.
About this store
The Billings store is the Purcell location in Montana for vehicle repair, running sixteen services, managed by Larry Wagoner. Belgrade, the other Purcell store in the state, is commercial only and does not offer air conditioning work.
See the national A/C service page for all 33 locations.