Yeah on that cot issue.... Matilda came out of the cot only because she was climbing. I would have kept her in it as long as possible because of the implications it had on sleep. For the 3 weeks before she slept through 5 out of 7 nights and went to sleep within 30 minutes. For the first 3 weeks in the bed it took us around 2 hours to get her to sleep at night & she was up & down all night long, the next two weeks took an hour and finally by 6 weeks she was settling in her bed. So I would say if there are sleep issues now, wait as long as you can before you do the big bed.