Mine were a tad older when their next sibling was born (2 and 9months and 2weeks shy of 3) but both were bolters at 2.5 and I was despairing. I've not bought a double though as I've always worn my babies so I figured I'd test the waters both times and by 3 they've grown out of both the need for a pram and bolting. Couldn't do without a carrier though and was still carrying DD at 4.