It is basically up to you and your flow! Our styles with a 4 or 5 tampons' worth of absorbency are absorbent enough to be worn alone even on your heaviest days, but if your flow is extra-heavy, they work great as an reliable backup too, if that makes you feel more comfy and secure. Our styles with a 0.5 to 3 tampons' worth of absorbency are great to use as back-up to tampons/pads/cups/etc or alone on lighter days.