I think we switched at 19 months when we weaned my girl
I agree with Sarah. For safety the crib is good until they try to climb out or in my daughter's case use it like a trampoline. We also potty trained our daughter at 2 so we started the transition just before potty training so that we could help her out and to the potty quickly during the training..our daughter did not struggle with playing with toys in her room, but did try to read her books and get stuffed animals. Be prepared every kid is different and it may take a bit to transition, therefore a lot of the time and energy, while also thinking of what may need to be done in anticipation.
My son is almost 3 and half and he has only just gone into a toddler bed and that’s because he climbed out of his cot and fell so we decided it was time
We only just did it a couple of months ago & my little boy is nearly 3. His cotbed was supposed to last him until he was 5, but it was creaking every time he turned over in it & waking him up, so we bought him a toddler bed in the shape of a digger.
@Sarah Thank you, my son is trying to climb out not gotten fully out by climbing but it's getting closer to the point where I believe he will be able to. He's also learning how to flip his mattress while still sitting on it.
My son is turning 4 this month and we will be giving him a twin bed. He started climbing at 1.5 but we turned the crib around (had a higher backside) and dropped the mattress, bought us another 2.5 years. Best decision ever.
I think this is more about development and safety than age. We had to convert my daughter's crib when she was 2 and she was trying to climb out so it was no longer safe. The reason I say development is because the minute you convert you have to deal with them being able to get out of their bed and then potentially out of their room or playing instead of sleeping. It's very important that you make the room as safe as possible and that you remove anything that you don't want them to play with. As my daughter has developed better sleeping habits we have been able to allow her to have her furniture and some toys back and we no longer need to have a baby gate outside of her door because she now understands that she has to stay in her room and she knows how to call out if she needs something (water, potty, ect.)