They told you right. How long do you want the A/C system to work before you have to replace every component in order for it to work properly again? You can do all of the work yourself with out pulling a vacuum and if you do you should flush the lines. When you don't pull a vacuum you won't get all of the water out of the system so you'll need to replace the accumulator as well. You should replace that every time you open up the system anyway.

Oh, and you can lose a finger to frostbite if there still is refrigerant in the system and you let the refrigerant out on your finger for too long. Hopefully your sensory perception should be high enough for you get the heck out of the way in time.
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'98 XC '95 855 GLT '83 245 DL (245 for sale! e-mail me if your looking to buy); All over 125k miles