For those who have assisted their little ones to sleep how long did it go on for?

DD is two and fairly dependant on me to get her to sleep, she's never been a self settler. It's just what we do no so i'm not looking at trying to get out of it but i'm just wondering about how long the dendancy carried on for? I'm more so just curious, i was lying with her as she went to sleep tonight and i had this picture in my head of her being in PS and possibly still needing me. Would this be the case?