pediatric sleep disorders expert. There's no set time when you have to replace your child's crib with a regular or toddler bed, although most children make the switch sometime between ages 1 1/2 and 3 1/2.It's often best to wait until your child is closer to 3, since many little ones just aren't ready to make the transition.Of course, you'll need to move your toddler to a bed when he's simply too big or too active to sleep in a crib anymore.t's often best to wait until your child is closer to 3, since many little ones just aren't ready to make the transition. Of course, you'll need to move your toddler to a bed when he's simply too big or too active to sleep in a crib anymore.