Here's where the marketing can slip away from reality. The puff count is often calculated with a low-power setting and a short puff duration. But many devices have adjustable airflow or higher wattage, which burns through liquid faster. If you use it at max power, you'll get far fewer puffs than claimed.

Another gap: battery degradation. Lithium batteries lose capacity over time, especially if the device sits on a shelf for months before you buy it. A device that's been in storage for a year might give you 70% of its original puff count. Not something you'll see on the label, but worth knowing.

Then there's the "up to" language. Manufacturers can legally claim the maximum possible number, even if 90% of users never get there. It's like a car's highway MPG—technically achievable, but most of us drive in the city.