My son was tiny (6 1/2 pounds, 18 1/2 inches long and one week overdue), so he definitely wore newborn clothes. He's three years old and is still in 2T clothes, though, so he's not really demonstrative of a normal kid. :) If you and/or your husband is tall, you probably won't have the same issue I had. My partner and I are both small (I'm 5'2 and he's 5'9).
um... JULY?!??! 1st ... weekly chat. - Page 5
I like to have a few sleepers and onesies that fit the 6-8lb size, but not too many because even my slow gainer outgrew them pretty quick. I'm talking a week or two.
It's kind of funny, my largest baby was 7lb11oz (the other two were 7lb3 and 7lb2) and yet she's pretty tiny as a 26mo old. She still only weighs 23lbs and wears 12-18mo clothes lol!
They'll always keep you guessing :)