According to the manual, the key batteries deteriorate within 3 ft of cell phones, computers, and even table lamps. Sheesh! I'm nearly always within 3 ft of one of those. Maybe I shouldn't read the manual after all...

 

I sure hope not... I bet 90% or more of Lexus drivers have their key in their pocket/purse within 3 feet of their cell phone.

"To avoid serious deterioration to you key, transport on your person inside of a 6" thick lead box."

 

Regardless, the battery is constantly being depleted while driving much different than your fathers Oldsmobile with the fob that just opened and locked the doors. Im changing the batteries after two years as preventive. Five minute job and the battery cost is negligible.