My Socks That Rock 100% merino and Angora Valley Fiber 100% merino socks, so far
, show no signs of wear in terms of thinning on the foot bed or heel flap. They've worn far better than I expected.
I've never tried nylon reinforcement
, when I saw a pair with the reinforcing thread and they felt a little rough for my feet (I didn't even wear handknit socks for a long time until I got used to the hand knit texture, the bottoms of my feet and backs of my heels used to get sore after only a short time of wearing. So I'd go back to commercial socks, but once I used a soft yarn and got used to it I loved 'em!).
I can see the thread cutting into the wool, but this could also just be theory, I do know that you're supposed to sort synthetics from natural fibers in your laundry because the synthetics will pill and wear the natural fibers when washed all together... I've also wondered if the wool would just wear away like normal and while it wouldn't unravel because all is held together by the nylon, you'd still have a hole or at least a very very thin spot where it's just nylon thread?
I'd be interested to hear others opinions on this also!