Have used this brand of sock for the last five years maybe, i have everything from the heavy mountain sock to sock liners for trainers, they are warm in winter and still comfortable in summer, thats the beauty of wool, warm in winter cool in summer, i general i replace socks after a year or so, your XL socks in general will drop a size every year from washing, one of wools drawbacks,
Over the last five years i have bought about forty pairs, so they are good, if i can i will buy for next year too, things are always cheaper now than they will be next year,
A good work boot sock is also the Royal Marine issue arktic sock youll find them on line, for about £7 a pair, a great wool sock too