10. You do the aftermarket math before you buy anything
You don't buy anything you can't flip. You think that makes you a good businessman, but instead it makes you part of the problem. Here's an idea: buy stuff you actually like, and want to wear. Maybe, down the line, when you decide you're tired of it, give it away to a friend, donate it, or sell it on the Internet on a forum to someone who can appreciate it as well as you didâ€”for less than the price you bought it sure, but still a better price than you'd get at a consignment shop.