Not often. But they do change overtime and you want to make sure you have a new crib that meets safety guidelines. For example, cribs made 15 or more years ago often had a drop-down feature that allowed one side of the crib to lower. This made it easier for parents to get their baby in and out of the crib. However, such features have since been banned since it is a safety hazard to have one side of a crib snap down with the potential of smashing a baby's hand, leg, or head with its weight. This is why using an old crib that was handed down may not be the best idea.