My Grandma has a central air conditioner that is 35 years old and still working great but it is a quality built central air conditioner.
Today's central air conditioner are lucky to last between 10 to 20 years before you need to replace them and the more you use the central air conditioner the less time it lasts.
The central air conditioner at my house went out at 10 years old but was a cheaper model and I hope my new one lasts longer than 10 years because central air conditioners are expensive to buy and expensive to have installed.