Put me in the tool department at Sears or on the Snap-on tool truck, and I'm like a kid in a toy store. Most of the time I get a grip on my wallet and walk out empty-handed, but sometimes I can't resist buying myself a trinket or gadget. That can be good or bad, and I never know which way it will be until several weeks or months later.
A torch tip cleaner kit I bought is a good example. It's a pencil-size gizmo that has a dozen teeny little drill bits stored inside, with a teeny little drill-type mandrel on the end. You select a drill bit, clamp it in the mandrel, and then spin the pencil-size housing with your fingertips to drill out or clean out clogged tips on acetylene torches. It was an impulse buy that cost maybe $15 that I regretted as soon as I wrote the check. But that little gizmo has come in so handy so many times that I rate it as one of my most useful, though rarely used, tools.
Another impulse buy that I had second-thoughts about was a set that contained a plain ol' metal machinist's ruler and a plain ol' metal caliper. Nothing fancy, just two decent-quality measuring devices that caught my eye at a moment when my buyer's resistance was low. But over the years I've been glad I bought them when I needed to precisely measure metal components. When you need to measure 32nds or 64ths of an inch, a carpenter's tape measure just isn't the best tool. And...I've been known to cheat and compare the "inch" scale to the "millimeter" scale on the opposite side of the ruler to translate metric measurements into standard measurements.
Not every impulse buy turns out to be a good purchase. I absolutely had to have a nifty relay tester when I saw it--I figured I'd use it all the time to test relays on computer boards. It's a really cool tool, and every so often I get it out and play with it. But I've yet to actually use it to test a relay.
That's the problem with impulse buys---they're a roll of the dice as to whether or not they turn out to be useful or not. Enough of my gambles have "worked" that I continue to occasionally yield to temptation and take a chance on a shiny tool that calls my name. Just like a kid in a toy store...