"When is it time to stop co sleeping? And I don't mean 'you must not share a bed past 18 months'. What are the signs that it is time to sleep separately, from an emotional/developmental point of view?
My son still falls asleep in my bed most nights. And the nights he falls asleep in his own bed he comes into my bed at some point during the night. I *try* not to make sleeping in his bed a punishment ("If you don't keep your head on the pillow you are going to sleep in your own bed tonight" has escaped my mouth more than once). And I like climbing into a bed that has been prewarmed, or waking up to my baby-turned-little-boy cuddles."
You can probably guess what I'm going to say by the fact that I put the word time in quotes in the title:
It's time to stop co-sleeping when it stops working for one of you.
Kids are all different, and some need to sleep in a certain place under certain conditions or they can hardly sleep at all. Others could sleep on a bench in Grand Central Station and get a solid 10 uninterrupted hours. Some really like to sleep with other people in the room, and others need to sleep alone.
Which sounds a lot like adults, too.
When you have a baby, co-sleeping or not co-sleeping is about principles, and How You Parent, and about what you think you should do. But once you have a preschooler it really just becomes about what makes things better for everyone involved in the equation tonight, because you know that it won't be the same in a few months no matter what you do.
The developmental signs for him are that he wants to sleep in his own bed. And the developmental signs for you are that you want him to sleep in his own bed.
If you and your cuddlebug like sleeping close, go for it. When one of you gets sick of it, it may be a big moment, or you may not even realize you've stopped co-sleeping until it's been awhile.
As long as you're being specific about respecting your kids' boundaries and teaching them to respect yours, do what works to get everyone as much sleep as possible.