Sammy
My LO is 3.8yrs now. He has ALWAYS slept in gro bags I even got the next size for 4 years old. He has always slept 12 hours.
At 2.6months I decided to convert the cotbed as "everyone" else was doing this. NIGHTMARE BEGAN!!!!!
He hated it full stop, wasnt used to a pillow, quilt etc... had 5 weeks of him waking 3 times every night. I did not give in.
Until I suddenly thought...he is so scared of bedtime, sleeping and was very, very stressed. I was exhausted, plus the cotbed WAS NOT as big as I thought.
I put him back into his cot, in his gro bag, for the next 8 months he slept 12 hours, like a baby and was back to his very, very happy selgf.
One day out of the blue, he asked for a big boys bed when we were at Ikea.....end of story!
Conclusion - if your child is happy, content, sleeps well do not move him. If you need the cot for a newborn - buy another or borrow one. Who says that you HAVE to move to a bed at 2.6? No one.
Hope this has helped