Is there anything that I am not allowed to store in my unit?

There are definitely things that may not be stored. For example, explosives, combustibles, ammunition, and toxic materials. Some things aren’t forbidden but aren’t a good idea to store. For example, you want to avoid storing food (aside from canned goods) or anything that should only be kept under specific storage conditions. An example would be a glass globe filled with water–they would likely freeze and break in the wintertime.