Auto Air Conditioning & Heater Repair: Keep recharging yearly, paper floor mats, dodge caravan

Question
I have 94 Dodge Caravan, and I need to keep taking my caravan recharging the AC yearly. I tried many regular repair shop and no one can find any leak in the system. Today, I took my car to a AC repair shop, he told me that the pressure is too high specially during hot weather. When the pressure is too high, system will release refrigerant or will cut out etc. The AC repair shop claimed that there is no leak with the AC system. Will the system release refrigerant from somewhere like valve etc when the pressure is too high? He suggested to replace compressor and drier etc. Does it make any sense? Seems like the guy doesn't know which component is actually defective, so he recommended to replace everything. What is average charge for the replacement of compressor and drier. I don't know anything about AC. Any advice would  be appreciated? Thanks.

Answer
Woody,
I apologize, I only answered half of your question. The Typical charge for a compressor and drier replacement can range from anywhere in the 400 dollar range to about 1100, max. Dependant of course on the cost of parts, shop's labor rate (typically around 65-95 dollars per hour), and most have a set standard rate for recovering and evacuating the system, that will usually account for about 100 dollars. Then they will charge you anywhere from 9-25 dollars per pound for the refrigerant they charge it back up with. And then there's always our favorite... shop fees that cover the rags and paper floor mats, etc.