We only have one set, but we do not need more than one per kid. DD2 is wearing dd1's old onesie-style undershirt and dd1 is wearing her shirt and pants from last year. I thought I bought dd1's big enough last year to last this year's whole winter, too, but the sleeves are getting rather short. Not a huge deal, she prefers her sleeves a little short anyway. The pants are just fine, but both are extremely riddled w/ holes! I take excellent care of them, mostly handwashing. I bought them from Palumba and was v impressed w/ the quality for the price, hrumph. They were something like half the price of Ruska (these are Hocosa brand). I guess I learned my lesson there & I will fork out the money & try Ruska next time. Are they really that much better? I need to know before I invest, lol!
Back to main topic, dd1 wears hers almost every day (the shirt at least) & b/c of the excellent airing out qualities of wool AND w/ how quickly they dry draped across a radiator, one set has been plenty!