Sigvaris Socks - Lack of Durability
Men's Sigvaris merino socks lack adequate reinforcement and durability in the heels. The heels of 3 pairs tore with 8-10 wearings and have had to be repaired.
I'll stick with Darn Tough hike/trek socks which will last for at least 12 months and come with a lifetime guarantee. The customer contact site doesn't seem to work and forward serious complaints about defects.