All rechargeable batteries eventually die. They can last a long time if charged properly.

The battery has what they call a memory and that determines how much charge it can hold over time. Improperly charging or lack of charging can cause the memory effect and thus... decrease how long the battery will be serviceable.

You are supposed to charge both keys fully at least once a year. So if you are the only driver... you need to break out that spare or the battery will eventually fail.

Placing your remote in the dash allows the car to charge it when necessary. People with the comfort access remote will almost NEVER place it in the dash and then not for that long. This is why they do not get a rechargable remote. They can replace the battery every few years and not have to worry about it.

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2007 4.8i, Space Gray, Dark Burl Walnut Wood, Black Nevada Leather

Packages:
ZCW Cold Weather, ZPP Premium, ZRC Rear Climate, ZSP Sport, ZTP Technology

Options:
217 Active Steering, 322 Comfort Access, 328 Running Boards, 496 Heated Rear Seats, 610 Heads Up Display, 655 Sat Radio, 840 Increased Top Speed to 150 MPH ,2LE 20" Y Spoke Wheels.

Mods:
Stainless Steel Pedal Pads