Extended service plan

Do we really need an extended service plan for our electronic equipments? I’m not really aware that there is such a thing until my friend advised me to get this extended service plan for our home equipments and electronic gadgets. She told me about her experiences as well as the advantages of this extended warranty. Somehow she was able to convince me but still I need more info and more testimonies from others. How about you? do you have any experience on extended service plans?