Surge protectors aren’t like diamonds. They have a definite lifespan. At some point, your surge protector will stop protecting your gear from power surges and become a dumb power strip.

It’s difficult to tell exactly when a surge protector loses those protective powers and just functions as a power strip. But, if you’re still using an old surge protector you purchased ten years ago, it’s probably long past time to replace it.

via Why (and When) You Need to Replace Your Surge Protector