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Lower the cot mattress to its lowest setting, remove anything your toddler could use as a step, and keep bedtime calm and predictable. Once your toddler can climb out of their cot, it's time to think about moving them to a "big kid" bed. As a general guide, it's also worth making the move once your child is around 89 cm (35 inches) tall, or when the cot side is less than three-quarters of their standing height.