Laptop batteries are consumable components. Good charge management and low heat can slow aging, but chemistry guarantees capacity loss over time. A replaceable battery can substantially extend the laptop's useful life.
What commonly determines lifespan
Capacity loss, high internal resistance, swelling, charge-management faults
This profile is an editorial summary of sourced lifespan context, common service points, maintenance leverage and repairability. See the linked methodology and primary reference before treating any range as a guarantee.