DS1 would always get out of muslin and cotton wraps and then wouldnt sleep. I got kidopotamous wraps at 2 weeks and then bought 2nd size! Used till 9 weeks old then straight to grobag.

DS2 is still wrapped in kiddopatamous wraps at 6 and 1/2 months as he wont settle without it even thought he tends to eventully get arms out.