My laptop computer already has a completely dead battery, even though it has seen infrequent use. Originally priced at $650, it is now worth $160 in good working condition on eBay. A replacement battery is $65 and requires professional installation for an additional $100; replacing it now makes more sense than repairing. The lifespan of a laptop battery varies depending on how it’s used, but averages between 18 and 24 months. This is planned obsolescence at its finest, especially since a user replaceable battery is now a rare commodity!