At some point, yes. You will have to replace your R22 air conditioner if it is either over 10 years old or if you are experiencing any problems with the unit. There are alternatives to R22 refrigerant out there, including newer HFC's and CO2 that could be used in an AC unit without negative effects on the environment. With that being said, newer models of air conditioning units are most commonly fitted with R10A which is deemed an "environmentally-friendly" refrigerant that, while more expensive than their predecessors, have been shown to be safer for the environment.