Because safety glasses are cheap, and you only get one set of eyes.
And, by the way, safety glasses make great gifts. Slip a pair into the Christmas stocking of somebody you love. You can never go wrong giving them safety glasses.
If you wear prescription glasses, you need to either get prescription safety glasses with side shields (they’re expensive) or go for a quick solution such as the boxy style that are roomy enough to fit over your glasses. They’re a hybrid between glasses and goggles.
An inexpensive option, if they work for you, are to get so-called reader safety glasses. These +1.50 are a good example of this class of product. In some cases, you can get bifocal styles.
If you want a good, rugged pair, it’s hard to beat the thick-framed and time-tested design of these safety glasses, known in the eyewear business as Clark Kents.
A Google hybrid with a face-sealing gasket provides more coverage and comfort, not only from flying debris, but when the conditions are particularly dusty and you need to shield your eyes from irritants lingering in or blowing in the air.
Safety glasses with adjustable frames are useful not only when you have to buy safety glasses for a group and you want to ensure a good fit, but the length-adjustable temples make for a better fit when you’re wearing a hat.
If you’re running a big crew of volunteers, do yourself and them a favor and buy your safety glasses in bulk. They are extremely inexpensive this way and if someone loses them, breaks them, or doesn’t return them, you’re not out a lot of money. Always check that the glasses for your crew (or yourself) meet the rigid ANSI Z87 standard for impact protection. This is a standard set forth by the American National Standards Institute, and it’s eye-saving.