My hubby and I use ours a few days in a row, sometimes a week. The kids share one and theirs gets washed after every bath. We have 3 (they all get washed in assembly line type fashion) and when the baby is done the towel can't dry anything else so it gets washed. My kids are still young so they don't get a bath every day yet unless they've gotten pretty dirty or sweaty playing outside.
For those that use a different towel on face/hair... have you ever used that one on the body after a couple of uses and then tossed it in the hamper. I know a lady that does that since she says it doesn't get as dirty as the body towel.