How many burp cloths do you need?

More than you have. I guess it depends on how messy an eater your baby is and how much he/she/they spit up, combined with how often you want to do laundry (um, it feels like every day). For the twins, we had about twelve burp cloths and that was not enough. I just bought eight more on amazon (Gerber flannel kind) that are bigger and more absorbent. Plus you'll probably want to keep an emergency burp cloth in the stroller, diaper bag, car, by the changing table, etc.