What should I know about auto loans and being upside-down on my car?

Being 'upside-down' (or underwater) means you owe more on the car than it's worth, which is common because cars lose value fast — often 20% or more in the first year — while the loan balance drops slowly. You get there by making a small down payment, choosing a long loan term, or rolling old loan debt into a new car. To avoid it, put down at least 20%, keep the loan term to 48–60 months rather than 72 or 84, and don't roll negative equity forward. Being upside-down matters if the car is totaled or you need to sell, since you'd owe the gap out of pocket; gap insurance can cover that. If you're already underwater, keep driving the car and paying it down rather than trading up. Shop financing separately from the dealer and get preapproved so you can compare rates.