I did it with DS1, until he was about 2. He would fall asleep really well with his bottle, it was like a security blanket. I was always worried about his teeth, but it was hard to break the habit (i'm talking from my perspective - I dreaded attempting bedtime without it). In the end he was surprisingly easy to wean, just a few nights of being unsettled and some crying. I swapped the bottle for a non-spill sippy cup of water.