Lots of places wont touch R12 because they dont have the machines for it anymore.I know the last shop I was at had R!2 and we were only like 1 of 30 or so places that had it.Let alone most dont have R12 to recharge it.We were getting 50 bucks a pound for it which was cheap.Changing to 134 isnt very hard.Usually just the conversion kit and a reciever.dryer.Did quite a few at work and almost all lasted and cooled decent.oh yeah 134 only uses IIRC 85 % of 12.You can pick up 1 pound cans at times.Just be careful we had sysyems at work that identifier said had benzyne,butane etv in it.Rocky