In the broadest category on the site there is no single rule, but there is a method that takes a minute.
Name the material, then the enemy
Paper — humidity and light. Flat or upright, acid-free, dark, dry. Plastic — light, which yellows it permanently, and heat, which deforms it. Metal — damp air, and sulphur from rubber and newsprint. Fabric — folds, insects, and sealed plastic. Glass and ceramic — contact and pressure rather than climate. Wood — humidity swings rather than humidity itself.
Almost every collectible is one or two of those, and the answer follows directly.
The four rules that apply to nearly everything
- Out of direct light.
- Away from an outside wall, off the floor, never a loft.
- Dry air, with silica in the box during the monsoon.
- Nothing touching anything else, and nothing stacked under weight.
Packaging
Where the box is part of the value, store the box as carefully as the object: upright, not crushed, and dry. Cardboard is the first thing to fail in a humid month.
Labelling
An unlabelled collectible loses value the day you forget what it is. Write down what you know while you still know it — edition, where it came from, when you bought it.
What it costs
Boxes, silica and a shelf in the right part of the house. The real cost is deciding where, and that is free.
Questions people ask
Is a glass cabinet good storage?
It is display, not storage. Out of sun, with airflow, it is fine for robust things.
Should I keep original packaging?
For anything collected, yes — and store it dry.
How often should I check?
Twice a year, and always after the monsoon. Monsoon and your stock.