Outside of the modding point which is a good one....
Pretty simple. Are you a payment buyer and live check to check somewhat? If so buy the warranty if you can afford the additional payment.
If you have the funds to coverage a major issue in the event that it may occur skip the warranty.
Odds are you will pay much more for the warranty that what you will get from it. But if you are working on a tight budget and a major repair could sink you buy the warranty.