Batteries, What, Where and how long they lasted.

It's coming to that time again to get a new battery, got my batteries tested today main came up at 21% 2 years old and Aux %52 one year old, on a century battery tester.
When I was down south I'd get 3.5 to 5 years out of my battery,
Since living in Darwin and North W.A, I'm getting right on 2 years.
I use to have Bosch Batteries, the ones from super cheap I think they where 600cc 4x4.
Since then I've replaced them with Century 600cc Marine Pro, which is still a lead acid but with heavier lead plates with supports.
Anyone used on of those smart chargers (ctek) after a Battery test and seen a improvement, I don't mean a test the next day or two but months later.
How long have your batteries lasted you? where are you? and what type? Do you regulary maintain them etc top up with distilled water, give them a charge on a mains charger?. Have they been used on corrigated roads?