We moved Natalie into the cot as soon as we got her room set up... Which wasn't until she was three months old (And she wasn't rooming in with us. We weren't very organised! She shared her room with our gym equipment until that point, LOL. Didn't seem to bother her, though I guess it was pretty disrespectful of us.) So. 3 months here, though she could quite happily have slept in her cradle for at least a couple more months.