Yes you are correct that once the battery dies you'll need to replace the device. But I'll tell you a secret...
Ask any long time user here (let's say been vaping 18+ months) how old their oldest piece of equipment they currently use is and plenty will say 6 months or less. Plenty more will be in the year range. Very few will give times over a year. So by the time that battery dies odds are that you're ready for something better / newer / easier to use / etc anyway.
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