Being useful better safe than sorry devices, most surge protectors don't have a long life span. You need to change them eventually, at most after a couple of years of use. Good surge protectors will not just start blinking the red LED when they have ceased to protect the plugged in devices from surges, instead they will switch off the power completely.
But remember to replace your surge protector after a couple of years of use. Moreover, a surge protector will not protect your device from lightening. On that note, experts also suggest you replace your surge protectors after any large event (lightning strike in your locality, multiple outages in rapid succession).
The best surge protector: Tripp Lite TLP1008TEL (10 - outlets, stops power supply when it wears out)
The second best surge protector: Belkin PivotPlug 12-Outlet Surge Protector BP112230-08 (supplies power even when it has stopped the surges)
The best compact surge protector: Accell Powramid D080B-015K ( six outlets, shuts power when protection fials)
The best surge protector for travel: Tripp Lite SpikeCube (only one outlet, heavy duty surge protection)