Ben Blatt is a reporter for The Upshot and an amateur woodworker who once received stitches for a band saw injury. What’s it worth to you to minimize the risk of cutting off a finger? $300? $600?

If you’ve ever caught yourself standing in the soup aisle at the grocery store skeptically eyeing the Tetra Pak of beef bone broth—which costs, say, $10 for a scant 16 ounces—maybe you’ve wondered how ...