By the time your baby is getting close to her first birthday, she will probably develop some favorites. She will have favorite foods, favorite toys, favorite songs, and more. Babies at that age have very pronounced ways of letting us know what they (and what they don’t like), and it will be fairly obvious which things baby likes best.
By the time baby is a year old, it is perfectly OK to let her sleep with a favorite stuffed animal or blanket. You should ensure, of course, that the toy or blanket meets safety standards and doesn’t have long ribbons, buttons, or other items which may present a choking hazard to your baby. Otherwise, there is no harm in letting baby have her favorite teddy bear or doll to cuddle up with.
When baby starts to develop attachments to favorite toys and blankets, you can even incorporate them into her nap and bedtime routines. Babies are much easier to put down to sleep, in many cases, if they have these familiar items to help soothe themselves with.
In some cases, children may continue to feel a need for attachment items well into their elementary school years. It’s best not to fight this, as it will eventually go away on its own. By the time you send her off to college, she’s really not going to need her favorite baby blanket and teddy bear. Most children outgrow the need for security items in the first couple years of elementary school, when they see that their friends don’t carry attachment items with them.
When your baby starts developing those kinds of attachments, and wanting a favorite toy to go to bed with, your best bet is to go ahead and let her have it. It will make it much easier for her to fall asleep, which makes your life a lot easier.
Attachment items, to your older baby or toddler, represent a sense of security. The idea that they can count on that particular toy or blanket to be the same, day in and day out, as they go to sleep, helps reduce a child’s anxiety by giving them something predictable in the midst of a world that often isn’t very predictable at all, especially for a child.