I have wool pants, called "longies", that I made to use as a diaper cover for my second child. She wore them for probably a whole year, as I made them long and folded the cuffs up for a while. They were made from a wool jacket, so they didn't have any stretch. Over time, they pilled (got little nubs of fibers all over them). As a mom who never irons clothes for her husband or children, I also am not a big worrier about stains (I never soak anything or use and oxi clean or any bleach on clothes), and I prefer to use simple eco-friendly laundry detergent. I confess that right now I'm using Target brand detergent as I had a coupon and it was on sale, but I HATE IT.
Back to wool care: I thought I'd take some photos and explain how I have taken care of wool diaper covers over 3-4 years.
Firstly, laundering them by hand is the best. Using a lanolin enriched laundry soap, like Eucalan, has been ideal for me. If you have a ton to wash, or are lazy like me, you can use your machine. I use warm/cold (our hot water is not very hot), and the delicate cycle. I use about a teaspoon (cap full) of Eucalan to every gallon of water, which I eyeball. I put the wool in (inside out) and the soap in as the machine is filling, and let it fill. I then let it gently agitate for about 30 seconds, to make sure the wool is saturated. Then I turn the machine off, leave it for 30 minutes, and then put the machine to spin. Hang to dry, gently shaking each item to get wrinkles out.

(here the top leg is shaved, the bottom is yet to go)
To care for the pilling, I use a wool shaver, sometimes called a fabric shaver or lint shaver. I bought mine at Joann's Fabrics with one of my 40% off coupons. It is handheld and battery operated. I should have invested in a stronger one! This one is fine, it just starts to putter about 1/3 of the way through one pair of wool pants.They looked significantly better when I was done, and after a good gentle wash, they will look great! My son has started on solids and the weather is warming up, but I will bet he will fit in these next fall!! I love wool, can you tell!?!?!