Dos-Dox said:
I rely on Zorbette Dry Tabs.
https://a.co/d/0dRznFsF. Because they're slim, they sit right on top of the vials inside a standard plastic kit, and the lid still closes without trouble. Once you start pulling vials out of the kit, a tab can also stand upright across 2 vial slots with the lid still fitting, so the size works out really well.
Color isn't an indicator for these, though they do become slightly soft and flimsy once saturated. Mine live in the freezer, so I doubt that's a reliable signal anyway. They cost so little that replacing them on a regular schedule is an option if you want to. For me they're just inexpensive insurance — not something I burn mental energy on.
I drop one into spice bottles and salt shakers too. No more clumpy garlic powder or salt! Before this I'd reuse one of the small silica packets that came with whatever OTC pill bottle I had, but I never felt good about clearish/white crystals in a paper or tyvek bag sitting in a shaker of salt. Sooner or later it would probably develop a pinhole.