Despite the name, a 'calcium' battery is still a lead acid battery - it just means antimony in the plates of the battery has been replaced by calcium. This means it's more resistant to corrosion but it does require a higher charge voltage than conventional batteries.
Personally, I'm a big fan of keeping it old school and seven years from a non-premium battery on a car that probably covers 5000 miles a year is pretty good.
If you're having battery issues then choose the largest battery that will fit in the car with the highest amount of cold cranking amps. Or get the multimeter out and look for electrical leaks.
Mike Powell, from the Morgan Sports Car Club, added that: 'Some 4/4's have the battery exposed to the elements under the rear floor so maybe a sealed, maintenance free or gel type would be preferable, but they are more expensive than conventional types and may require a special smart charger.'