My car/battery is 3.5 years old and still going strong and i can leave it for a 7-10 days and it starts no problem.
However the car is in the garage mostly between nov and march on a ctek trickle charger.
They only cost £50, well worth it
Black MY2010 Black Edition, Litchfield Stage 5 - Switzer P800 turbos, Litchfield suspension, Alcon 400mm front and 380mm back discs with Pagid pads, circlips, front and rear cameras, auto folding mirrors & lots of CF. Advan RSD wheels!