My original ATV battery lasted 6 or 7 years. The replacements have all been major disappointments. 2 years if lucky. Coincidentally I have not been riding the ATV near as often, so the battery does not get charged or used as much. I know this has an effect on battery life. I now use a battery tender (trickle charger) and keep it plugged into my ATV battery most of the time.
The Kubota battery is still going strong. 8 years old now and it cranks it over like new. I've never had to charge the battery in any way. Just turn the key when I'm ready to use it and it starts. Gotta love it. I hope I can get 12 years or more out of this battery.
Battery Tender is a good addition to any garage. I have 3 of them. With boats and ATV's I need them and use them regularly. They will help ease any battery issues you might be having.
beep beep....he went that way Wile. Did ya see him?