Most people think multimeters are just for electricians and electronics hobbyists. But when you notice your phone charging slower on some outlets, or you’re staring at a drawer full of mystery batteries, a multimeter becomes incredibly useful. This guide covers the practical stuff: testing outlets for voltage problems, checking if batteries are actually dead, and catching electrical issues before they burn your house down. Based on real experiences finding a 130V outlet that killed a drill charger and loose wires that were sparking orange instead of blue.