All too often parents make this transition too soon. My advice on this matter is loud and clear.
“Keep them in cribs as long as possible!”
When young toddlers are moved too early, they often don’t have the maturity that goes along with the freedom. It is just so tempting to get out of bed! When children are closer to 3 years old, they have a much bigger capacity to understand and follow the rules of sleeping in a “big kid bed”. Do you want your 18 month old wandering the house when you’re sleeping? Quite a scary thought! Sometimes when parents have a good crib sleeper, they are unaware of the bedtime and naptime battles that can arise when moving their toddler to a bed. Remember: cribs contain them! No sides on their beds means that they can get in and out of them, play in their room, get out of their room and into things that are potentially unsafe—the list of problems goes on, so if you feel you’re ready, make sure that you have a game plan for potential roadblocks! Of course, there are many toddlers out there who do just fine being moved to a bed at a young age; as a sleep consultant, I tend to see the gong shows!
The best advice I can give is to make this change because your child is ready, not because you need the crib freed up for a new baby or think they’ve reached a milestone age. My recommendation will always be that if your toddler is newly two years old when baby is due, buy a 2nd crib. You do NOT want a sleep disaster/regression on your hands with a newborn!
Another tip to remember is that you can change your mind! If you see that you’ve made the change too soon, it is OK to move them back to their crib. Please don’t think of it as a failure, but instead a developmentally appropriate decision. You will probably thank yourself for making that call if your toddler is just not ready yet.
Finally, if you feel that you and your child are ready, don’t hold back: get excited and go for it! Take your child shopping for big kid bedding. Get them involved. Make it a big deal. Be sure to have a family meeting to discuss the expectations and rules that go along with sleeping in a ‘big kid’ bed. If you make things positive and clear for them up front, you will have fewer challenges along the way.