I have 3 brothers, and whenever a sister in law runs wool through the washer/dryer I get the result. Sometimes that is good, but I just got a cashmere sweaer that is too small for a 9 year old.
Think that how much it shrinks depends on how much it was processed. Rag wool, the kind that stinks, shrinks the most. Marino wool dosn’t seem to shrink at all. I buy 100% wool socks, in mens medium, and run them thru the washer/dryer to get them to fit. The shrinking makes them a LOT thicker. Seems that once they have shrunk that’s it, as I continue to wash them with everything else. btw use vinegar in the wash to get the stink out, along with the jeans the kid pizzed in. I use vinegar in every wash, with no problems.