1999 Chevy Suburban Air conditioning wont hold a charge.

Well firstly, if your system is not holding a charge then you have a leak no question. But your system is fairly new so I cant understand why so many problems I would just be carefull of these mechanics that say all this stuff is wrong and probably isnt, second and third opinions are always a good thing and doesnt necessarily mean you have to pay for them. I would shoot some tracer die in the system myself the see if there is a leak and where it is, then take it from there, if you need anything else just let me know