My son is 6.5 weeks and he is just getting too long for the NB clothes. I will have to pack them away later this week ::cue sobs:: he still has plenty of room weight wise though, but he is tall and lean.
Around 3 months. The joys of having a slow gainer. I actually thought 3 month size meant it was supposed to start at 3 months, 6 month start at 6 month, etc. until she was 9 months old and catbus told me.
Wait, what? I thought that's what it means.
Eta: mine outgrew carters nb around 4 weeks, but other brands more like 7.
Somewhere between 6-8 weeks. He'll be six months on Sunday and still fits on some carters 3 month stuff, six months clothes he's got room to grow, most of it is quite baggy on him.