I too have a pair of German military issue pants that I've worn every winter season for the last 15 years. Before that, my brother was using them (don't EVER tell him where they disappeared to!) I've washed them a grand total of ONCE! The weave is very tight, and dirt or blood that gets on them, once dry, just brushes off without leaving a stain.
It's the only wool I've seen that actually does cut the wind. With any of the jackets I've looked at I'd want a more windproof *outer* layer.