I think I speak for (nearly) everyone here, when I say we've all done the math at some point and thought the same.
When the money drifts off in small streams it's harder to notice.
After being stupid with my money enough times my answer to solve the problem was setting a budget for my collection. And I say "stupid" because there's no other word for it. I didn't think of my purchases, sometimes at all and other times just not enough. Nothing like being in your 20's, single and free of obligations...