I bought nike ballistecs 1.3 for this reason. The concept seems nice at first, but there are caveats:
1. You must clearly wear through the sole to the foam. If the shoes wear evenly, this becomes a problem because on shoes like the 1.3s the rubber will go bald (no more tread) before you hit the foam. So for a while I was playing with bald shoes.
2. You pay for shipping back to nike in Oregon. I've read some people here that bought from TW returning them directly to TW, but I didn't so I had to return to nike. This can be pretty expensive if you want to make sure they get it (signature confirmation) so they can't lie to you about not receiving it.
3. There's 2-3 weeks between the time you send the shoes back and the time it takes to issue the voucher for new shoes. The voucher is only good for the nike online store and may not cover the cost of shipping + tax. You could order cheaper shoes, but that's not really the point (you want two pairs of durable shoes). For example my voucher came out to $120 exactly. The main point here is that you will have a few weeks were you need a second pair of shoes in order to keep playing tennis.
In the end I probably spent $145 total. Bought the 1.3s new for $110 + $10 tax. Wore them out. Ship them back for about $15. And payed an extra $10 for tax that wasn't covered. So that's really $72.50 a pair plus a month or so of time where I was either using bald shoes or my extra pair of cheap shoes.
The shoes were good for about 3 months before going bald. So I guess I do get 6 months worth of "shoe" assuming my new pair lasts equally as long. But if you can find a $50 shoe that can last 2 months, that may be better and more convenient than the whole warranty process. There are also some cheaper shoes or sales that come with 6 month guarantees. But I just don't like the dead time between wearing out the shoes.
