Washing every 2 days is fine. I personally wouldn't go more than that.
Mrs b - prefolds are awesome! I use them with DD3 but I use flats with the older two if I have to, being in tassie with the crap weather and all!
Audax - don't get too excited - the gf's are custom ones I had made with extra snaps so I wouldn't get wing droop. Added bonus is they last for ages!

