Going fom cot to a big kids bed

I was just wondering at what age did you transfer your children from a cot to a bed and how do you tell if they are ready?

DD1 was 18 months because I was pregnant and due 4 months after that and I didnt want her to think I was kicking her out of her cot for the new baby so we did this on purpose.

DD2 was about 22 months old she was trying to climb out of her cot which was a bit dangerous.

DS well he shows no signs of climbing out but he is a big boy so im not sure when we will transfer him, he has a thomas bed for his birthday its a full single bed but low to the ground so im thinking he will be in by 18 months too

DD was 14months. Needed to prepare for new bubs

DD was 16months old. She had previously gone to bed pretty much no hassles and self settled, when all of a sudden she started having these huge hissyfits everytime we took her near the cot.
Took me about a week to figure out that she just didn't want to sleep in there. Preferred even the floor to the cot.
On a hunch I borrowed a foldup bed from my mum and voila! A sleeping child.
We were moving a month after that so she slept on the fold out until we moved (600km) and then we just bought and put her new bed into her new room. She went straight onto an ensemble of regular size, but as she had co-slept for a long time she was aware of the edge of the bed and so never fell out even without a bed rail.
Many suggest getting them to pick their own linen etc but at that age she was too little - heck she still doesn't particularly care now.

DS went into a bed before he was 1, though due to the age we put a bed rail on. He has never slept in a cot and always slept with me (this must be prefaced with has always refused to go anywhere near the cot). He's never even really looked like falling out but he's still so little.

Thanks for that DD is still only 14 months and has no concept of the edge of things that are high so I might have to get a portacot for this next one until she is ready

DS was 18 months. He was a terrible sleeper, had never slept through the night once in his whole life so we thought we'd try a big bed because the sleeping couldn't be any worse. I was pregnant with DD and my tummy was getting bigger and it was getting harder to rock him back to sleep and put him back in his cot without bumping my tummy on the edge of the cot.

And he miraculously slept through the night that first night in his big bed...it wasn't the instant end of the night waking but oh my goodness he slept more soundly and woke up less and less.

DD was 15 months...also because I am pregnant but she suddenly started waking up more when previously she had been an amazing sleeper so we thought we'd see if we had the same success with her brother...and yes, she is sleeping better again in the big bed.

However she is more of a wriggler than her brother ever was and has fallen out a couple of times despite having bedrails, she wriggles all the way down to the end of the bed, past the length of the rails. We have learned now to check on her before we go to bed to make sure she is at the correct end of the bed - usually she is about halfway down the mattress by our bedtime so we put her back onto her pillow and she never makes it back to the end of the bed before morning comes.

DD1 was 15 months, DD2 was 18 months (or 16 months, can't remember now).
Reason I knew both times was because they would wake themselves up at night as they were too big for the cot.

16 months here but only because she wouldn't sleep in her cot anymore. If we didn't have that problem I would have kept her in the cot longer.

2 years 3mths why?? cause at our holiday place he slept in a port-a-cot and he was getting to big so we tried a single he did so well we decided to pull cot down at home and set up a single the next week never looked back, he had never tried climbing out