Self-storage facilities have a surprising number of regulations on what you can and can’t store in your self-storage unit. Cleaning products, paint, pesticides, oil, and fireworks are just some of the items prohibited in many self-storage facilities. Many facilities limit tire storage to a single set (4 tires). Even items like bird seed can be prohibited due to a fear of attracting pests.
Contrast that with your rent to own storage building. There are no restrictions on storage except the ones you make up! Leftover construction materials, gardening supplies, animal food; it’s completely up to your discretion!