My 2009 Wee is still on the original battery.
I expect 5 or more years from a original battery and 3 years from a aftermarket one but here down under we ride all year round.
Fitting a volt meter can tell you when your battery starts to show it's age and needs replacing.
Some of the 19 rides in my shed
2014 V2, Snoopy
2009 Wee, Pumbaa the pig
WR450F, The Blue Postie Bike
YZ250N smoker with rego, Stinky.
Yamaha MT09 (FZ09), The Scud missile.
Club Lead not Club Med.
He with the most toys wins.
Out of my depth in a puddle.
Live life on the edge you will see more that way.
Ridding a motorcycle keeps things in balance.
At the end of each trail and at the end of each day history is made.