Many people turn down extended warranty plans on purchases because they have homeowner's insurance and believe that the item will be covered under that. Often times it may be, but not always. That is why it is important to know exactly what type of coverage you have for certain possessions and what is being offered in an extended warranty at the time of purchase.
If the manufacturer or retailer is offering technical support as well as replacement or repairs, it may be worth it. You have to judge for yourself if there is a likelihood that you will need technical support with the product. You also should consider the homeowner's insurance deductible on your plan versus the cost of an extended warranty or service plan.
In some cases your typical homeowner's insurance will provide you with the coverage you need. In other instances it might be better to get the added protection of a product service plan.