Very bad impulse purchaser, I am. I particularly hate it when someone else buys a locomotive off eBay that I'm watching. If I get time to come up for air this evening, I'll post photos of my latest impulse purchase from Mr. Muffins.
To help keep my impulse purchases at bay, I keep meticulous spreadsheets of my model railroad acquisitions, including date purchases, when they were received, exactly how much I paid for the item(s), who I bought them from, etc... This helps me visualize the amount of money I'm throwing at this "hobby".
Anthony