Short answer. eBike batteries last 500 to 1000 full charge cycles, which is three to seven years for most riders. Life span depends on cell quality, charging habits, temperature exposure, and how deeply the pack is discharged on each ride.
Step by step
Charge to 80 percent for daily use. Full 100 percent charges shorten life. If you only need 30 miles, charge to 80 and top off before a long ride.
Avoid extreme temperatures. Charging below 40 F or above 110 F damages cells. Store the pack indoors year round.
Do not let it sit at 0 percent. A pack left dead for weeks can drop below the BMS wake up voltage and become permanently dead.
Get an annual health check. A yearly capacity test tracks decline and warns you before a road failure.