i start my boy with pull up pants when he start crawling (around 8 to 10months old)that is when it is hard to use taped diaper as they will flip and start to crawl away.
My baby 3 mnth I change to pull up already as he already so chubby...
I changed to pull up pants nearing 3yo when toilet training.
I changed after my LO started walking
When baby start walking