Many people choose to purchase a used car for obvious reasons – it’s cheaper than buying a new car of course. Still, that doesn’t mean every used car purchase makes financial sense, particularly when you are borrowing to pay for it.

This article explains why many people can’t really afford the used cars they are buying.

Ly crunched the numbers for used vehicle sales following the “20/4/10” standard where used car buyers put down 20 percent, take out a loan no longer than four years and spend no more ten percent of their monthly income on a car payment.

Using that formula, iSeeCars.com found people in some cities like New Orleans will spend 140 percent more than what’s ideal over the course of that vehicle’s life.

The “20/4/10” standard is a pretty useful guide for most people, so you can use that as a starting point when evaluating car purchases.