A few weeks ago I called Merrell customer service (which was immediately answered by a real person) to ask if there was a way to thicken up the bottom of my shoes (it was starting to feel as if there was nothing between my foot and the rocks). She said no, but that she can send thru-hikers one new pair for free. Now that's customer service!
My shoes actually held up really well after over 1400 miles. Hardly any tearing or holes. In fact, another hiker was happy to take them when I got my new ones! They may end up on Katahdin after all.