Our nanny uses a Maclaren twin techno for the two babies aged 7 and 13 months (it's a nannyshare!) but also walks the 3-year-old to and from the 5-year-old's school and his own pre-school.
However, the 3-year-old has recently been diagnosed with arthritis for which he is being treated. He's a good walker but when his arthritis flares up can barely walk.
One solution would be for the nanny to carry the smallest baby in a sling but she's not the lightest baby in the world! I wondered about a Strolli and if this might be a useful back-up.
Has anyone use one with a double buggy or with a 3-year-old? If so, how did you find it in terms of clipping it on and off the buggy frame and how did your 3-year-old respond to it?