lots of good answers here, i was also thinking of them in terms of replacements after your main ones were torn up from walking for days/weeks in earthquake/whatever rubble.i saw a shot in the canoe trip blogs where a guy had some really hard core looking boots and the front of the sole came off the bottom.he patched them up with small zip ties thru the sole and into the edge of the boot that were pulled tight.the photo before he trimmed the zips was almost humor....