You might wonder why every online vape shop asks for your birth date or makes you scan your driver's license. It's not to annoy you. In the United States, federal law sets the minimum age to buy tobacco products—including vapes and e-cigarettes—at 21. States and local jurisdictions can add their own rules, but 21 is the floor.

Online retailers can't see you in person, so they rely on automated systems to confirm you're old enough. These services are the digital equivalent of a cashier checking your ID at a physical store. When a site asks for your date of birth or the last four digits of your Social Security number, it's usually because a third-party database is cross-checking that you're a real adult. Some services take it a step further and ask you to upload a photo of your ID.

A surprising number of adult buyers hit a snag here and assume the store is being intrusive. I've spoken with people who abandoned carts because they didn't want to share their SSN or scan their license. But here's the thing: that friction is actually a sign the retailer is taking compliance seriously. A store that skips verification entirely is either cutting corners or operating outside the law.