Key Fob

[jimsea]

I have a 2003 Ford Ranger that I bought new it is 25 years old and the key fob still works in the spare key that I never use still works how long does the battery last in the key fob

 

[rumblecloud]

F-ing forever!!
My 94 is still kickin' == both of them in fact.

Seriously though I have no idea.

 

[pentode]

I have a 2003 Ford Ranger that I bought new it is 25 years old and the key fob still works in the spare key that I never use still works how long does the battery last in the key fob

Well-designed transmitters with a halfway decent battery can last crazy long. They only wake up for a millisecond every now and then to see if they need to work.