My car is going to be 12 years old at the end of this month.
It doesn't get driven too much so it goes in once a year for service/inspections.
For the past two years the dealership has been keeping the AC system on life support, saying things like "we gave it a boost and you should be good for the summer".
Those days are over. It no longer blows cold air and is in need of replacement. To those with knowledge of these things, would you A) let the dealership do the job or B) Go to a regular auto repair shop to try and save a few bucks?

 

Fixing an AC is a commodity repair. Usually independent shops are half the cost of the dealer, and either will do the job fine if they are honest. There are a lot of deceptive mechanics and dealers, so ask prople you know for recommendations on who to trust.

 

If you know a trusted mechanic, go there as it will literally cost at least half or less than the dealer.

 

Since it sounds like you have leak in the system it would be best to find someone with decent AC tools/equipment and is willing to check the system for the leak with a good leak detector, otherwise whoever you decide to take your car will be throwing parts at it and that can get expensive. Ideally the leak can be found and it's a simple fix or at least a single component to replace. You might also consider getting an electronic leak detector and check yourself, you can spend more time looking for the leak and there are some decent inexpensive leak detectors available now too. You'll save the shop time looking for the leak and save yourself money if you can find the leak ahead of time and then take it into the shop for the specific repair.
Common areas for leaks are the condenser (rock hits) and the compressor shaft seal but the leak can be anywhere. Whoever you consider to do the work ask them how they'll proceed to troubleshoot the problem and this can give you an idea if they are experienced and know what they're doing.
A word of warning about auto AC parts, there are many really low-quality aftermarket parts out there so don't waste time and money on crap parts and why it's better to pinpoint the problem if possible and buy quality replacement parts.