lifetime warantee doesn't usually mean the consumers lifetime it means the expected lifetime of a wetsuit. They would have expectations on all their different wetsuits and would repair anything that didn't meet it. (or did you already know that.....sorry if i missed the irony, text does that

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If i sell something that has a lifetime warantee and it has an expected life of 20 years and something goes wrong with it before it expires, the manufacturer will either repair it to last 20 years or will pay out the pro-rata price of the item. ie if it was stuffed after 10 years normal use they would refund half your money.
it would be hard to place a lifetime on something like a wetsuit as they are all used so differently.