Foam is usually the first part of a pad to wear out. After cushioning lots of falls over the years, foam can become lumpy, flat, and lifeless. When this happens, it’s wise to retire the pad from climbing and perhaps repurpose it as a bed for your pet.
Some pads — including offerings from Organic Climbing — can be refilled with fresh foam that is available from the manufacturer upon request.
The lifespan of a pad depends on the frequency of use and quality of materials. But, you should expect to get at least a few years out of any good-quality option.