When should you move your baby from his baby bassinet or co-sleeper to a crib?
First, if your infant is comfortable in a crib, then make the switch right away, so said an article I read. Some babies may enjoy this type of sleeping right from the start, rather than sleeping in a cozy baby bassinet. There is no need to wait for age or size to determine the move since a crib is designed for small infants up to toddler-age children.
Crib Bed
However, if your baby seems to be snoozing fine without a crib, then the following are a few things to keep in mind when making the change. Most babies outgrow bassinets at 3 months of age. So, if your baby is reaching this age, it's time to make the transition to a crib.
Once your baby can move around and/or sit up, a bassinet is too small and dangerous for him. An infant has no concept of gravity and does not yet possess the skill to hold himself up with falling out of a bassinet, which is not constructed for mobile infants.
Do not put pillows and stuffed animals in a crib to fill it out since these items are SIDS (Sudden Infant Death Syndrome) risks. Infants have been known to suffocate to death in soft pillows and toys.
To make the transition from a baby bassinet to crib a smoother one, get your child used to being in a large crib. Perhaps let him play in his crib for a while during the day. The article recommends letting him watch you tidy up from his crib.
I let my daughter get used to her crib by putting her in it a few minutes and having her mobile entertain her. I eventually put my daughter down to nap in her crib before she started sleeping in her crib in her own room at night. Then when she was ready, she slept in her crib through the night with no problems.