We just HAD to stop at 4 months , this week, cause it is too darn hot here, and we don't have central air! Unfotunately it is still a little rough, cause he still flails his arms a bit, and bonks himself or knocks out his binkie and can't put it back and thus wakes himself....we just quit cold turkey, and we let him cry for about 10 minutes at a time,and then go in and comfort/give the binkie back every 10 min or so....it has taken about 1/3 hour of htis for him to go to sleep/stay asleep each night of the last 3 nights since we stopped the swaddle. One book I have read that promotes swaddling for new babies says you can "wean them" by first swaddling with one arm out for a while and then with both arms out, and then stopping. We tried that, but with one out he would get the other out, and then get mad and cry and get all tangled up in the blanket, so it worried me so we just got rid of it altogether, and it is so hot now, he is just in a diaper/onesie, when winter comes, it will be footie PJs or a sleep sack.
Good luck!
Jessie