DS was 7lb 11 when he was born, and I was really glad to have some 0000's for the first few weeks. I was a bit sentimental, cos I bought a special "first clothes" outfit, which was a 0000, and I'm glad I did, because it was a nice fit on him. Think he wore 0000 for around 4-5 weeks but can't remember precisely. For what it's worth, Target have some really good 1 piece suits, which I personally like much more than the wondersuits as the cotton feels softer. But that's just me.