Car-Buying Mistakes That Could Cost You ThousandsRyan Lugo - MotorTrendOver the years, I've noticed that customers often do things that don't make much sense or pursue strategies that make buying a car more difficult and time consuming—even impossible in some cases. Here's a short list of some of those mistakes.Don't Neglect Your CreditGood credit is power. Bad credit will cripple you. Nine times out of 10, when somebody gets a great deal, it's because of their credit, not their negotiating skills.Some financial advisers say you should never finance a car, you should always pay cash. That's all well and good—if you have 50 grand lying around. Most people don't. It also ignores a basic fact: We live in a credit-based society.getty images - Getty ImagesWhen you only pay cash and never finance, your credit suffers. Credit is kind of like muscles. If you don't use it, you lose it. For that reason, everyone should start building credit at an early age and occasionally exercise it as they grow older, even if they don't need to, just to make sure they stay in good financial shape. If you want the freedom to buy whatever you want when you want it—or when emergencies arise—you need to maintain your credit and stay in good standing.Be PreparedWant to save time? Be prepared. When you buy a car, you'll need a current driver's license and current insurance card. If you're trading in a vehicle, you'll need the current registration for it or the title if it's paid for. If you have poor credit, you're going to need proof of income (POI), such as your last three paystubs, and proof of roof (POR), such as a power bill or some other bill coming to your residence showing you actually live where you say you live. Gather all these items before you go to the dealership. If you don't, you can waste a lot of time and potentially have to make a second trip.Stop Coming in 15 Minutes Before ClosingWho goes to a restaurant right before closing with a party of 11 expecting to be served? Yet people will stroll into a car dealership 15 minutes before closing expecting to test drive "three or four cars" as if it's nothing. I'm sorry, folks. This isn't Buc-ee's. We're not open 24/7. Most salespeople have wives and families, and occasionally we like to see them. When you ask me to stay two or three hours past closing, it's an act of supreme selfishness. And it's not just me you're keeping late. It's the sales manager, the finance manager, and the detail department. You won't get a better price.Stop Asking Mechanics What to BuyThis may come as a surprise, but in my opinion it's a total waste of time to ask a mechanic what kind of car to buy. Why? Because mechanics are human beings just like the rest of us, and all human beings have certain preferences and biases. I had three uncles growing up. All were mechanics. One was a diehard Chevy man. One never owned anything but an Oldsmobile. The third was a Chrysler man. (He was the black sheep.) They all believed the cars they drove were superior to every other car on the road. And they all knew what they were talking about, backed up by decades of experience. Who was right? They were all right. But it was just their opinion.getty images - Getty ImagesIf you ask a mechanic who makes their living working on Japanese cars what to buy, they're almost certainly going to tell you to buy Japanese and avoid German or American cars. If you ask a mechanic who works on German cars, they're going to tell you to buy German and avoid Japanese or American cars. It's just human nature. Do you think someone who works on Toyotas is going to recommend a Hyundai???Stop Trying to Buy a Car for Someone Who Isn't ThereMen, you can't buy cars for your wife. It doesn't matter if you've been married for 50 years. It just doesn't work. Trust me on this one.When It Comes to Research, Quality Is Key, not QuantityMany people who show up on car lots these days suffer from "research fatigue." They've been online shopping for cars for three weeks, and their heads are so full of information they don't know which end is up. Everything's a blur.AdvertisementAdvertisementWhat's more, they study the wrong things. For example, who looks at the overall history of recalls on a particular model? No one I know. But if a particular model has had 70 recalls since it was introduced, and another one has only had seven, it may be an indicator of future reliability.Stop Trying to Shop RemotelyWant the best deal? You have to be there. Period. A car dealership is like a busy restaurant. If all the waiters have tables full of customers clamoring for their attention and you call in wanting to chat about maybe possibly booking a reservation two weeks from now, you will be put on hold. A car salesperson focuses on the customer who is sitting right in front of them, cash in hand, ready to buy. Not some wise guy on the internet who isn't even there.Stop Financing for Long TermsPeople who put nothing or very little down and finance for 72 or even 84 months to get the lowest possible payment are making a huge mistake. You should put down as much as you can and finance for the shortest term you can tolerate—like 36 or 48 months—to get into a position of equity as soon as possible.The reason is, you're going to get sick and tired of that vehicle long before 84 months is up. (By the way, financing for 84 months is insane.) And when you try to trade out of that car early, you'll find you've added a huge amount of negative equity to the price of your next vehicle by financing for that long. Plus, you're paying a lot more interest. Don't do it.Stop Lying to Your SalespersonMost buyers believe salespeople are liars so, in their minds, it's OK to lie to them. The problem is, first, lying is wrong, no matter who does it. Second, you're only hurting yourself. Example: If you tell me your credit is good and I pencil payments based on good credit, then I later discover that your credit stinks and the best rate you can get is 29 percent, not 7.9 ... who have you helped? Lies won't get you past the credit app.AdvertisementAdvertisementLet's say you tell me Jerry down the street offered you $25K for your trade, and I know Jerry personally. So I pick up the phone and call Jerry right in front of you and ask him if this is true. If it isn't, then we'll all know you're a liar, and you'll feel like a fool. What is the benefit?getty images - Getty ImagesOr suppose I ask you if you're trading your current vehicle and you say no, because that's what all the experts tell you to say. "Negotiate price first and then drop the trade on 'em later!" First, I'm going to ask you a few questions to see if you're lying, like "Oh? What are you planning on doing with it?" If you stutter and don't have a plausible answer right away, I know you're lying. And later, after we're done talking price, guess what happens if you say "Y'know, I think I've changed my mind. I'd like you to look at my trade." I'm going to give you less, not more, for your trade. If you'd been straight with me from the start, you might have gotten thousands more. Lying almost always backfires—on the one who lies.Don't Fall in LoveFinally, the biggest mistake you can make is falling in love with a car. Cars are just things. Chunks of steel, rubber, and glass. Depreciating assets. Ultimately, their purpose is to get you from point A to point B. If you fall in love with a vehicle, your salesperson will know it, no matter how hard you try to hide it. And there goes all your bargaining power. You should never decide based on emotion. That's what your salesperson wants. You should make your decision based on logic and your budget. Love your wife, love your kids, love whatever your passion in life is, but don't fall in love with an automobile. It will never love you back.