Nicky outgrows his wardrobe

Nicky was born a mere 5 pounds and 1 ounce; he started with premie outfits and a few newborn size pieces, now he's finally moved one from everything he wore at first. I literally took everything out of his drawers to replace it with the next size up. My little peanut is a whole chunk bigger.
The next step is to figure out what to do with all the stuff he outgrows: keep some, donate some.. I can't decide.. it's all so new, and it's hard to part ways with his little outfits.