Impulse purchases are almost always a bad idea.* You spend money on something that sparkles and winks at you when your defenses are down and before long you find yourself wondering "What, in Heaven's name, was I thinking" (and by the way, where did all my money go)?
Now, antiques are a whole different story. I've learned the hard way (on a handful of occasions) that when it comes to antiques (or any other vintage or one-of-a-kind cool thing), the rule is: "Buy it now—it sure won't be there later" (and by the way, where did all my money go?)
Being broke really cures you of impulse shopping (or antique shopping, or frankly most other kinds of shopping as well). The value of a dollar becomes so crystal clear, it pings. While this kind of clarity is a good thing, I do tend to get kind of obsessive over using up every last scrap of food we buy. To throw food away is like tossing cash straight into the garbage can. Oh sure, it can be put into the compost bin so it's not totally wasted... but that's some mighty pricey compost. You might even call it rich.
So here it is... my confession... I made an impulse purchase. I couldn't help myself. It was such a good deal, and it sparkled and it winked at me. So without thinking it through, I bought it. I bought a 5-pound bag of limes. My justification was that as a seasonal produce item, it fell under the Antique Rule: it may not be around next time (if it is, the price will certainly be a lot higher). Besides, think of the wonderful things I could make with them!