DS was a sicky baby, so spent quite a bit of time sitting up. Having said that, he rolled at 6w so he must have spent some time not sat up! He was sitting on his own before we started using a baby chair, from memory.

I think I pretty much did this. DS spent quite a bit of time sitting on my lap (clingy/sicky baby) and in the carrier, but he was pretty much allowed to do as he wanted most of the time. He rolled early and walked early - I remember him lying on his back, grabbing my hands and hauling himself to his feet! That was just over 6m old. But he was an active baby in the womb too, maybe that had something to do with it?