I personally recommend keeping a child in the crib as long as possible (in fact, they make a 'tent' cover that you can keep them from climbing out and hurting themselves that I recommend).... like til 3 yrs old!. The reason .... my son is 7 and we converted him to a toddler bed at 2 yrs old ---- and he has NEVER slept in his own bed, all night long, by himself since! After you take them out of the crib, they then have the ability to get up/ out/ move around all on their own, whenever they want. And you will end up sleeping less too -- putting them back in their bed --- time after time after time (Or sleeping with them in your bed or theirs because you get too tired and fall asleep!). I recommend keeping them in their crib as long as possible ---- it may just be enough to convince them that their room/ bed is a good place to be when they are old enough to reason with!