http://arnott.smtusa.com/faq/index.asp

# How long do air suspension parts last?
The air springs normally last 80,000 to 100,000 miles. Over this time, the rubber bladder dries out and cracks around the bottom piston. Compressors usually wear out due to leaky air springs. For the most part, the computer and height sensors normally last the life of the vehicle.

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