Why should I switch to golf cart 6v batteries

We prefer to dry camp and our 2 - 6volt Trojan T105 batteries have been ideal. Bought them in the summer of 2008 and I do my best to not let them drop to less than 50% charge. No signs yet of any decline in performance. When we conserve we use about 18AH per day and can dry camp for about 6 days.

Used a single 12v deep cycle before 2008 and never have been able to keep it in good shape for this long.