I have several pairs of wool undies and much prefer these over other brands. I've had big problems with durability. Not sure if the others just start to disintegrate on there own or if I have bugs on me (or in my drawers, but i don't think this is the case since my other base layers are also stored in the same place and they are all OK). I loved my wool undies so much that I kept on getting more even though they only lasted a year or so. These so far have been holding up great. The fit, feel and quality are just as top notch as icebreaker, i liked icebreaker's direct contact with the NZ farmers... not sure how smartwool treats their sheep or farmers, but at least these last.