They will lose some of their elastic and also get a bit thin. But it sounds like you only have one pair and they'll wear out a lot faster. Get some more, they aren't that expensive. You don't have to shop at the Rapha shop, just get some PI or other brand, or even Performance/Nashbar. I like the pair I got from AerotechDesigns at a bike fair last year and they were pretty cheap. I have Castelli, Descente, PI, and some others too. All are good.