I'm 36 weeks and just finished mine.
For me - 3 pairs of pajamas, huge cotton underwear, slippers, comfy socks, breast soothing pads, and a small toiletrie bag (travel size items)
For baby - 2 swaddle blankets, 2 sleepers, 2 outfits, socks, mittens, a hat
37+3 and just packed mine today, mostly packed at least :)
I say 36weeks at least start. Mines finally finished, 38 weeks now. I have loose shirts and pants(stretchy.) I have to get a nursing bra and now a button up pj shirt so I'm not completely done. I packed clothes for my man and pjs, clothes for baby plus receiving blankets since hospital blankets stay there. Socks, mittens, and soft beanie for baby. Slippers for me, old underwear since we will be bleeding some pads. My hospital said they provide diapers, wipes, and pads for us. And I'm going to have my mind take snacks for us. Maybe cereal bars, jello, juice, lite items. I also washed the baby's clothes. I might go thru my bag again. Lol since I'm just waiting for her arrival. ;-)
34 weeks. I think they ladies said that was the latest to pack. So I guess around 30-32 start packing.