My friend uses a maintainer— he gets 6 years out of optima battery
I don’t use a maintainer or charger I got 16 years out of last optima,have 10 so far on this one.
At hershey there is a tent with only maintainers and accessories and the guy tried selling me one by saying it would double my battery life so I asked him if I bought his maintainer would my battery last 30 years—- he said NO so I asked him what it would increase the battery life by so and he said that it would extend the life of a battery from 2-4 years to 4-6 years.
I am not afraid of burning up my generator,I do drive 50% at night with halogen bulbs— my charge rate is 14 amps which is 1 amp over having the lights on.
regular cheap batteries went 7-9 years.
If I go on a 50 mile daylight trip part of the time the headlights get turned on.
Of course if your car is modified it may need some help keeping the battery charged.