Don't think I will need that much! .
It is possible that both of you have the same quantity of actual Nic stashed though! Maybe he only vapes like 4mL of 1-2mg eliquids per day, and you vape 5mL of 12, 18, or 24mg per day! Big difference in how long his would last...compared to yours, even though you might have the same actual amount. Just sayin'...you technically could also have 66+ years of nic and just don't know it!