Washing baby clothes

I need to get on the roll and start washing our daughters clothes. I went a little over board and I bought so, so, so (too) many things. I thought about just washing the newborn, 0-3, and 3 month items for now and then washing sizes as she grew into them. That way if things didn't fit during the right season (we live in the south, so sometimes cold seasons aren't actually cold and the hot seasons are just wet) then we could attempt to return or even sell them privately as lots of clothing. I liked the idea of leaving them unwashed and with tags on since they would be of higher value. 

A family member suggested that that was a lot of work (I don't really think so. You're talking 10 minutes of snipping tags and a load of laundry since the items are so small.) 

What would you do/did you do/are you doing? All at once or just as you need sizes?