A newborn will snooze just about anywhere, but at some point you’ll probably want her sleeping in a crib. For this second entry in our “Product Evolution” series, we got some expert advice on how and when to change your baby’s sleeping environment—plus product picks for each stage.

Start cozy. “Newborns like a snug feeling while they are sleeping,” says Janet Kennedy, Ph.D. (a.k.a. the NYC Sleep Doctor). “The best way to accomplish that is with a tight swaddle. Most people use a bassinet, moses basket, or co-sleeper at first.” But “some children sleep exclusively in their crib from day one, and that’s just fine,” adds Conner Herman, co-founder of Dream Team Baby. The baby should transition to the crib (start with naps) once she is un-swaddled, rolling over, too big for the bassinet, or when the parents are ready to move the baby out of their bedroom. Magic Beans founder and baby-gear guru Sheri Gurock recommends the Arms Reach co-sleeper, the Monte Ninna Nanna Bassinet, and the Stokke Sleepi System 1, in bassinet mode.

Lower the mattress. “It’s important to lower the crib mattress before it seems necessary,” warns Kennedy, “because you don’t want to learn the hard way that you have an escape artist on your hands. Once the baby can roll over, it’s a good idea to move the crib down from its highest setting. Absolutely move it down mid-way once the baby is sitting. And as soon as the baby shows any interest in pulling up or standing, move the mattress down to the lowest setting.” Gurock is a fan of the Stokke Sleepi and Oeuf Sparrow cribs.

To tent or not to tent. “If the child is a precocious climber, it could be worth trying a crib tent,” says Kennedy. “But in general, I prefer moving the child to a bed once he can get out because the crib escape signals a developmental milestone—that the child is probably emotionally ready to be in a bed.” Herman, however, recommends keeping children in the crib until around age 3, even if they’re climbing out. “Until then, toddlers are impulse-driven and not generally emotionally mature enough to understand that even though there are no sides, they are not supposed to get out of bed.” If you choose to use a crib tent, Herman suggests thinking about it as a temporary solution—“something you do initially for safety reasons, and then take measures to teach your child to stay in the crib.” Gurock suggests trying the Tots in Mind Crib Tent.

Toddler vs. Twin. “The difference between a toddler bed and a twin is really just a matter of space,” explains Kennedy. “If there’s room, it’s best to go straight to a twin. When children leave the crib behind, they are making a big emotional transition. A converted crib still feels like a crib in most cases. Children can get more excited about a new bed, and they will be more motivated to rise to the challenge of being a big kid (i.e., staying in bed).” Gurock’s favorite twin bed is the Oeuf Sparrow.

Guard rails. “Guard rails are important for physical and emotional security, even if the mattress is on the floor,” advises Kennedy. Herman agrees and adds, “Once you feel like your child has adjusted to the new sleep space, you can remove the guard rails and line the floor with pillows for a few days. If your baby’s sleep habits don’t change and there aren’t any accidents, then you can be confident that your baby has successfully reached the finish line.”