When to Replace a Fire Extinguisher. Even if there’s no expiration date, it won’t last forever. Manufacturers say most extinguishers should work for 5 to 15 years, but you might not know if you got yours three years ago or 13. So how can you be sure it will fire away? Atlanta fire chief Dennis L. Rubin recommends checking the pressure gauge monthly. “If the needle is in the green area, it’s functional,” he says.