Question: how long can you go without changing a pad?
Answer: On your heavier days, you may need a more absorbent pad and on our lighter flow days a less absorbent one will do. No matter how heavy your flow is though, you should change your pad at least every 3 or 4 hours so you don't end up with an odor from bacteria that can grow in the blood. Yuck! As often as you need to.