I take it real easy with wool; all wool. I still have King of the Mountain wool which is preshrunk and supposedly very washable; it mostly is, but I had a shirt Jac go from an XL to a postage stamp while following exact instructions. Yes, they did replace it.
On my merinos I choose to wash cold and slow and air dry. I'm not saying you'll run into problems going more aggressively than I have but I'm just not in a hurry anymore.
