At least in my experience. 2006 GS 300 (bought new in Sept 2005) & just replaced battery for the 3rd time (i.e. now on its 4th battery). South Florida vehicle with 86,000 turnpike miles (traffic usually freely flowing 70-75 mph), wife's commuting car. It is garaged at home and at work. The second battery died at 49,997 miles so at least warranty covered replacement twice! Dealer attributed short lifespan to the heat here and computer complexity of the car , but my 2004 BMW 530i battery lasted 4 years.

I would suggest you have the charging system thoroughly checked. I agree the battery should last longer than that. It is possible you have a problem with your alternator that is causing the battery to die prematurely.

I agree. Load test your alt.

something is draining the battery (parasitic)
or the battery is not getting a good charge.

Take it to Autozone and they will load test the charging system for free.

steviej

I have had my GS300 for 4 years and i never have had to change the battery

I also have an '06 GS300 and I live in Las Vegas. There aren't many places in the world much hotter, but my original battery lasted 52 months. I travel extensively and even when leaving the car unattended for 4 weeks at a time, it always started right up. I agree that there must be something wrong with your charging system or you've got a parasitic loss.