when i first started vaping with a 1300 mah battery, it would last about 10-12 hours, so i would have to change it out. needledd to say, i was a chain vaper. i just noticed a few days ago that my battery is lasting me 24-28 hours! this must have happened very gradually...as i never noticed it before. i guess i am vaping much less than i was. hubbys battery that is the same size lasts him 3-4 days.