I am usually in a position to forgot what I ordered or purchases when it comes to vinyl albums. I'm a collector, and have thousands of albums. It's almost impossible to remember what I already have when I get to the record store, and sometimes I buy albums that I already have. I've done this a few times.
With regard to reloading;
I'm currently re-opening my reloading bench that has sat idle since 2006. Most of the hardware (presses, dies and similar) for the bench were purchased in the early to mid 90s, so the hardware alone is beyond my recollection of purchase, and I was surprised to see what I had after all these years. In about 2002, I bought a bunch of brass, bullets, primers and powder. I mean a big bunch. As I'm going through my inventgory now, 16 years later, I am shocked at how much of some components I have. I probably have enough 9mm components to keep me busy for many months of reloading. Unfortunately, I sold my 9mm and 380 firearms over 10 years ago, so I'll probably have to get one 9mm handgun just to use the components up.
I have to start a spreadsheet for my inventory. Otherwise it's going to stay out of hand.