I know in another thread one of the creators has gone 500+ miles with multiple washings in them. I'm only at about 20 miles, 3 weeks of WODs, and 1 washing but I have say they are very durable. I love having them on my feet, and actually I love the strange looks, I don't mean to be an attention whore
but hey, I don't mind being a free spokesman.
I have noticed it takes roughly 2 weeks to get used to them, as all feet are different, my left foot took a couple days longer to get used to them as my feet are roughly 2 mm different, which doesn't sound like much but it can have an effect on size difference. I am very glad I went directly to a store and tried them on rather then purchasing them online. I have only worn them for running and working out, and I plan to keep it that way, so I'm guessing they are going to last quite some time. I like my Nike flip-flops for just walking around as they also have a very low sole, but are more durable then a $5 pair from Walmart. For any watersports like kayaking or boating the Vibram shoes would be a perfect match.
I will caution people, you do feel large rocks if you happen to step on one, but you don't get a huge gash in your foot. You will also notice that the propensity to suffer from a rolled ankle is next to nothing, which me with multiple rolled ankles from basketball shoes can attest to. I find this a God-send, as I have noticed my ankles have gotten a lot stronger since using them. My feet and calves have gotten stronger, and I haven't feel any pressure on my knees at all since getting the shoes and being forced to forefoot strike. I've always been a forefoot runner, but I'd notice as I got tired I'd try and stride out, which is purely a form thing, but without any padding on the heel, you know right away if you lose form.
Hope this helps!