EV batteries degrade gradually, not at a fixed age or mileage. The Department of Energy’s analysis of 15,000 plug‑in vehicles shows fewer than 1 % required replacement due to failure from 2016‑2023. Normal aging means a modest loss of range; today’s packs typically last 12‑15 years in moderate climates and 8‑12 years in extreme ones, with about 2.3 % capacity loss per year.

Drivers should watch for persistent declines under comparable conditions, not temporary drops caused by cold weather, climate control, speed, hills, or added weight. Abrupt symptoms—sharp range loss, charging limits, reduced performance, or battery‑system warnings—signal deeper issues. Tesla, for example, issues high‑voltage alerts that may limit charge and range; other makers have distinct warning systems.

A qualified service center can run battery‑health diagnostics to determine whether a pack needs replacement or if other factors are at play.