Just stop. Please, stop it. It's killing us to see you killing your A/C. You may not know you're doing
it, but your poor A/C system needs some professional help. You mean well, but you're killing it.
Stop adding canned refrigerant. Yes, it comes with a gauge, yes it's cheap and convenient, NO it is NOT good for your car! That gauge isn't always accurate - many times it will cause you to over or underfill your A/C without you knowing. You'll put one gauge one and it will say you're under, but the next one will say you're over, and you're at a loss - which do you go with? Overfilling your A/C can also cause your air not to blow cold, but it can also cause damage to your system. And the contents of that can be quite questionable. There is sometimes refrigerant, but there is also oil, stop leak, and more that could cause damage to your compressor based on what brand you buy. Those contents can also damage a shop's A/C machine, a pricey piece of equipment by itself. Some shops will not even attempt to recharge your system if they know that you have used canned refrigerant.
Stop ignoring that noise. That grinding noise, the weird on that kicks on and off. Of course, you shouldn't ever ignore ANY noises, but this one is going to make your A/C repair that much more expensive. When your compressor starts to go out, you will hear the bearings inside grind as it intermittently kicks on and off. Over time, those bearing will grind down and the metal shavings will be sent through your system. When that happens, you have to replace a good portion of your system and have your lines flushed out to get rid of the metal shavings to keep them from damaging your new compressor. On some vehicles, the A/C compressor is powered off of the same belt as your alternator. That means when your compressor goes out and locks up, you could be stuck on the side of the road with no more power to your car! If you ever have a worry that your compressor may be going bad, it's always best to just take it to your mechanic to have them check it out.
Stop simply recharging your system. Ok, this doesn't necessarily kill your A/C, but it is a HUGE waste of money. When the air stops blowing cold, simply recharging will not keep it going. Your system is a closed circuit, so if you're recharging, there's likely a leak somewhere and all of that refrigerant is just going to come back out. When you have your system recharged, be sure your technician injects UV dye in the system. The dye can help your technician hunt down a leak a lot easier, as it will push out at the area the refrigerant is leaving. Having this done could end up saving your hundreds or even thousands in constant recharging.
Please, please, please, for the love of all that is good, please stop killing your A/C. You will be miserable, your passengers will be miserable, and your wallet will be miserable. If you ever have any issue with your A/C, don't hesitate to talk to your local mechanic. Here at PMR, we are more than happy to recharge, dye, and check out your A/C system. Just call us at 618-998-9010 to schedule an appointment to have your system checked. Need to stay cool before your appointment? Check out our article about staying cooler without the A/C.