How long does a Bosch eBike battery last?

Bosch guarantees their batteries for 2 years or 500 charge cycles (whichever comes first).

This doesn’t mean your battery will pack up after 2 years and 1 day. In fact, Bosch themselves state that the battery should be good for around 10 years or 1500 full charge cycles.

After 1500 cycles the battery will still work, but any battery will age over time so it will start to lose capacity and therefore not power your electric bike as far.