Any placeable that:

1. Has an inventory
2. Is Plot
3. With not script

… will be automatically turned into a persistent chest so that its inventory never “disappear”.

You can have as many of them as you want. You are only limited by the number of non-static placeable allowed per area.

You will never loose what you store inside a persistent chest but their inventory may become inaccessible when you add or remove another persistent chest from your house.