It’s winter… car air conditioning doesn’t matter!
Actually that is not strictly true.
Air conditioning units have a cooler-drier that removes moisture from the air in the car and helps remove condensation rapidly. When the outside air is cold and icy, condensation starts to build up in the car the moment you get in, due to your own body heat. You find that although you have scraped ice away to clear the windscreen, you are driving off with obscured vision because of moisture condensing on the inside. Admittedly you can use a leather to keep clearing away the build up, but that takes a hand that should be controlling the car and is also an unnecessary distraction.
When something doesn’t work we tend to think the worst and several of the air conditioning components can be expensive to replace. However, if the air-conditioning is not working it may simply need re-gassing as over time the efficiency of the gas decays. Alternatively, since frequently the pipework can be susceptible to corrosion or stone damage, it may be that only one of these may need replacing. If in doubt you you can always ask for an assessment, you might be pleasantly surprised by the result.
Finally, one of the first things a prospective buyer of a used car will ask is whether the air-conditioning is working. Since the repair cost can sometimes be minimal it is always a good idea to have it repaired. Cars that have something very obvious in an unsatisfactory condition, generally have other hidden problems, making sure the car has working air-conditioning is therefore a wise investment.