How long does an air conditioner work? What is the life span for room ac? How long an air conditioner can be used?

Centralized air conditioners are designed for heavy duty applications, Hence that can be used for 10 to 15 years depending on their usage.
Room air conditioners are smaller units and designed for 8 hours daily runtime only, that can be work for 3 to 6 years depending on their usage and environmental conditions.