A service plan is an optional warranty that is offered to purchasers of products for an additional fee.
For example, a lightning strike is considered an environmental cause, and consequently is excluded from most service plans, even if they claim power surge protection.
Some items like home theater equipment are repaired on-site with the retailer covering the cost.
Whether an extended service plan is worth the extra cost depends on the item and the perceived value by the consumer.
Some items such as low-end headphones may consistently fail before the end of the coverage period, which can be advantageous.