Think about the old metal file cabinets. There were separate drawers with hanging file folders and then subfolders. A good organizational strategy allowed you to find the documents stored in there.
Without a good strategy, many people may just stuff papers into any drawer in no particular order. Later, they need to find the information but end up having to look haphazardly through the drawers and file folders to find that information. The papers are in there, but are not easily retrievable.
How do you organize your digital files on your computer? Are they scattered all over your hard drive? Are they kept in many different folders? By not keeping your files more centralized, and in searchable folders, they will not be easy to find, nor can you be assured that they are being backed up.
There are many different strategies that can be used. I have included a couple of examples below, one for photos, and one for documents.