how much trouble to put ac back on?

hi dan just to let you know the only time a filter drier needs replacing is when it has absorbed enough moisture to not allow enough refrigerant flow through it. that only happens when a system runs in a vacuum therefore sucking moisture and air into the system. most a/c systems prevent that by using a pressure control that cuts the compressor off at about 20 psi thereby preventing a vacuum to occur. so the next time someone wants to sell you a new drier you can ask them why. Paul