Definitely need to exercise that bike at least twice a week, with a solid 1/2 hour of highway speeds. As much for the battery as for the engine itself. All that short putt-putt riding is condusive to moisture buildup in the crankcase and oil.
I used to live at least a 1/2 hour from everything I did when I lived in a small rural town in east central Wisconsin. I would ride daily from April 1st to December 1st, so at least 45 miles a day, all highway. I had no Battery Tender then, and the original Mareg battery lasted eight seasons and was still useable when I replaced it with a Westco. At that time I relocated to Green Bay, and worked from my home. My daily 45 mile ride reduced to a weekly 100 miles at best.
That Westco battery suddenly died after less than two full seasons. Right after a long 800 mile weekend.
I replaced it with a Toyo battery, and use a Battery Tender now. Going on season four of the Toyo battery this year.