I also have 3 girls, 3 different sizes (even though the first 2 are twins). I pretty much saved everthing while it's still being worn (if someone fits it) but I'm picky about when Rivka outgrows stuff what to save. If dd3 has a lot of nice clothes, I might put some away for dd4. I found that it only takes 1 stain to ruin an outfit, and it really stinks to have 15 outfits of girls clothing and have to go out and buy somthing b/c the stuff is worn / has a stain / etc. I will also say that for plain weekday clothes, by the time the twins have worn it (usually for 2 seasons) it's already past prime when it goes to Rivka (okay for preschool / around the house, but not so nice anymore kwim?). By the time Rivka's done for it, it usually goes out. I have saved some of her stuff that's really in good shape, but a lot of it winds up going out.