How long does your Optima battery last?

I've had the same red top Optima battery for over ten years now. It has been in my 1970 Challenger RT 383, 1965 Pontiac and now my 1970 duster. I never had to boost the battery in all that time. I do use a AMG battery charger during the winter months, that charges the battery and then feeds it a trickle charger as it is needed