The appropriate time to stop using a crib is usually when the baby can climb out or reach about 35 inches (89 cm). This typically occurs between 18 and 36 months, but it can vary depending on the child’s development and activity level. At this stage, transitioning to a toddler bed or a mattress on the floor can provide a safer sleeping environment. It’s important to ensure that the new sleeping arrangement is safe and comfortable for your child to prevent any accidents or disruptions to their sleep routine.