If your detector is 8 years old, then yeah, it's probably due to be replaced. Mine went after just 6 years and started giving false alarms. I finally unplugged it, then replaced it before our next trip. No more problems now.
Mark & Joyce Noeltner along with Cricket the Chihuahua
and memories of Chico the Chihuahua (Sept 2002 to Sept 5, 2013)
2005 Fleetwood Fiesta 26Y
2001 Jeep Cherokee Sport