Melissa, if your DD wriggles her way out of the wrap and you want to continue wrapping, get a larger wrap Otherwise, if she is content sleeping without it, just go with that... No rules that I know of
Loulou, my DD is the same age and I wondered for a while about moving to a sleeping bag (although she can't roll all the way over just yet) but I guess she would need to free her arms to be able to roll over in which case she'd be able to position herself properly on her tummy if she did end up there, kwim?