With proper maintenance, your electric scooter battery will have an average lifespan of 300-500 full charge cycles. This is typically 2-3 years for the average rider. The age of the battery is not nearly as relevant as how many times the battery is charged. After several enough recharges it starts to lose its potency.
A full charge cycle means charging a fully discharged battery, i.e from 0% to fully charged 100%. This is rarely done however…most likely, you’ll charge from 30% – 50% full to 100% full. That means you’ll get 600-1000 cycles before the battery will need to be replaced.
If you ride long distances every day, expect between a year and two years before it’s time to change the battery. If you ride less than that and charge it only one or two times a week, it will probably last longer than 2 years and maybe even double that, if you take care of it properly.