Babies can typically start using a crib from birth, but many parents prefer to use a cradle or bassinet for the first few months. Cribs are larger and provide more space for a growing baby, making them a good option for long-term use. By the time a baby is around 3 to 6 months old, they may outgrow their cradle and be ready to transition to a crib. The exact date may differ depending on the baby's size and growth, as well as the parents' choices and living situations.