Medina and Navares agree that the crib and mattress do not have the biggest impact on your child's sleep. Still, creating a safe, comfortable space for your baby is a great way to start. "The single most important thing you can do to get your child sleeping well is teaching how to fall asleep independently, without the assistance of any sleep associations or sleep props," says Medina. Ensuring that your child feels good in their crib and all of the safety precautions are taken only aids in this process. Nevares adds, "Sleep and development go hand in hand. Once they're getting great-quality sleep, then their development skyrockets." Thus, anything a parent can do to improve a baby's sleep, including finding the perfect mattress, contributes to your baby's development.