My ‘08 (17,000 miles) original battery is about 13.5 years old. Rather than store vehicle i drive it for about an hour at least once a month during winter, when the roads are dry. A battery tender is occasionally hooked up and disconnected when green light goes on. Based on my experience i don’t see a need for disconnecting battery terminals but a quality battery tender may be worth hooking up once a month. (A veteran BMW m/c mechanic advised me not to have battery tender hooked up for entire winter, just periodically until green light goes on, then disconnect.)