Another vote for indicating desiccant gel, you know for sure when it's spent. I got a 1lb can for ~$23 US from
BioQuip (an entomology supplier). I keep everything but what I'm using at the moment in a not particularly tight drawer in a file cabinet with a container of desiccant, and replace it when it changes colour. I use a small sour cream container with holes poked in the lid, with a few tablespoons of desiccant. No mould so far, even in our dank old farmhouse in the humid part of the year. I got it because I did have mould on the outside of a leather lens case once. It's fine so far...
Julie