Smartphones are useful for a lot of things. You can even use one as a ruler in a pinch. Generally speaking, you won’t replace your trusty yard stick. A phone is simply too small for anything other ...

The pupillary distance (PD) measurement is a requirement for people who want to purchase eyeglasses. Here, find out how to measure your PD using a mirror and a ruler. Share on Pinterest Some eyewear ...

This story originally appeared on Ars Technica, a trusted source for technology news, tech policy analysis, reviews, and more. Ars is owned by WIRED's parent company, Condé Nast. Cooking instructions ...