My youngest son is now a year and eight months old, and boy is he growing up fast! Well, I guess that that's typical of babies his age. That's why when I choose baby clothes I pick out those that is slightly bigger than his current size. If I don't, then some of the clothes (that I will be buying) he wouldn't get to wear at all!
I almost always buy clothes that are on sale, too. I mean, honestly I don't see the point of buying casual clothes that are so expensive; but that's different for formal wear, of course. :D