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What is the difference between “good debt” vs. “bad debt”?
First of all debt is a technology that allows borrower to bring forward their spending; it's a financial time machine. From borrowers point of view debt is good when it increases overall economic utility.  A young person wants to bring up a family but cannot afford the house. Had they waited for 30 years they would have reached the level of income and savings to buy the house for cash. By the time it might be too late to raise a family, sure they'd enjoy the house for the last 20 years of their life. But they would loose 30 years of utility - they could have enjoyed the house for 50 years! So, for a reasonable fee, they can bring the spending forward.  Another young person might want to enjoy a life of luxury, using the magical debt time machine and bringing forward their future earnings. They might spend 10 years worth of future earnings on entertainment within a year and have a blast. Due to the law of diminishing marginal utility - all that utility is pretty much wasted, but they'll still will need to make sacrifices in the future. The trick is to roughly match the period of debt repayment to the economic life of the purchase. Buying a house means paying over 30 years for an asset that has an economic life of 80 years+, given that the interest fee is reasonable and the house won't loose it's value overnight that's a good debt. Buying a used car with a remaining life of 5 years and financing its with a seven years loan - is not a good idea. Buying a luxurious holiday that lasts a fortnight with 2 years of repayments, i.e. financing non-essential short term need with medium term debt is insane. The other question is could the required utility be achieved through a substitute at a lower cost without having to bring the spending forward or paying the associated fee.