Battery Life
 

How long should a MB battery last?

From two to five years.
Depending what model.
What year.
How many miles you do.
Where are you. Temperature matters.
ETC. ETC. ;)

I believe a quality brand battery will last about 5 to 6 years of normal service. In the US, most batteries, irregardless of brand name, are manufactured by just a few large companies like Johnson Controls. Spiral batteries, like the Optima brand, seem to have the best life. But they don't have a size which fits Euro vehicles without some adaptors. Check out Optima on the web.

Also keep a trickle charger on it, when stored etc.

Not a battery charger, a battery tender or trickle charger

Five years is a good battery; three years is a bad battery. I always use Interstate batteries and I always get close or over the five year mark.

* Pos, I'd second that Interstate recommendation. I sold Interstate batteries in my first shop for over 15 years. The batteries fit the MB battery trays, come in the right electrical capacity, and the company's warranty policy is generous (they'll usually provide a replacement battery even if the problem is not clearly theirs). I'm selling (only) Interstate again in my new MB shop (for the older cars).
* I believe I read somewhere that Interstate is Daimler's official choice for a replacement battery in the USA.
* Getting 5 years out of an Interstate battery, even in a diesel in the colder latitudes, ought to be routine. Of course, it should go without saying that that's contingent on good engine and battery maintenance.

Thank you guys for the help . I installed a Interstate battery today.