Is it better to replace both the heating unit and a/c unit when the A/C unit has developed a bad Freon leak. This is the inside units.

Can the leak not be found and fixed?, if not, yes it is necessary to replace the evaporater coil because it needs to be a match to the new condenser unit more than likely the new outside unit will be a higher seer and will not be as efficant if not matched set,, also most companies will not warranty the condenser if it doesn`t have a matching evap. Coil and right size line set from one to the other