I keep most parts in the little mylar envelope with the vendor's label on it so I know what it is and where it came from.
Some, these days, have big, humoungous packs of desiccant in them to keep them dry. Thinking it might be a good idea to maintain that, I keep the packs and the indicator in with the parts.
Well, I picked up envelope of TPS60100PWP "Charge pump regulators," and it flipped in my hand due to the mass of the desiccant packs and something flung into the great unknown 42nd dimension. Yup. I now have a mylar envelope full of desiccant, but not the little strip with the parts.
Dang, those are expensive too!
When I get pack from the post office, I'll crawl around with my flashlight and jewler's loupe looking for them.