Most shoppers ask, "How long does it last?" but they ignore how the device is used. Two customers with the same 1500mAh battery can get wildly different results if one vapes at 20 watts and the other at 8. Wattage is the real driver of battery drain. Higher wattage pulls more current, so the battery empties quicker.

Another overlooked factor is the coil resistance. Lower resistance coils (like 0.2 ohms) need more power to heat up, so they eat through battery faster. Higher resistance coils (1.0 ohm and above) are more efficient. So when you're advising a customer, ask about their device settings, not just the mAh.

Also, puff duration matters. A 3-second puff uses more battery than a 1-second puff. That's where a calculator becomes useful—it can estimate how many puffs you might get, but it's still an estimate.