Regarding directory (or folder) structures:
I've been using computers since the early 1980's, so I've used a lot of different operating systems. The file management has gone from allowing only 8-character filenames to allowing 32-character filenames, to today's"long filenames" which appear almost unlimited -- until you bump up against the limits.
Look at this example filename:
Counting every character, this is 75 characters long. The current Windows limit is 264 characters (if I remember correctly). Notice that includes the drive name, the full path name, the filename, and the extension.
This could be readily shortened to:
And now it is only 56 characters long.
I use a system that would be described as wide, but not deep. That is, I have nearly 80 different sub-folders under "media" -- birth, death, marriage, yada-yada-yada....
One of those sub-folders is "census", which has nearly 55 sub-folders (one for each census year that I am tracking).
None of my media paths have more than 3 sub-levels, and I keep each folder name as short as possible (maybe 15 characters or so for the long folder names). That leaves all of the remaining 264 characters to be used as descriptive file names.
drive + top level + 3 sub-levels = about 60-70 characters. That means I could have descriptive filenames up to about 190 characters without bumping into the Windows limit, and, in practice, I think my longest filenames are about HALF of that.
So what happens if you violate the 264 character limit?
Your file may actually exist, but won't be visible in typical Windows dialog boxes (such as the Open and Save dialogs). That can be scary. I once helped a friend who thought he had somehow lost a whole group of files when he was re-arranging his hard drive. As a reasonably-experienced computer user, but not of a techie mindbend, he was befuddled. It turned out that he had violated the Windows 264-character limit by creating a file organization that was deep, rather than wide. He had as many as nine (maybe more) levels, and then used longish filenames to help him remember what was what. It made a lot of sense to him. We solved his problem by shortening the names of the sub-level folders, thereby getting his longest total path length inside the limit.
Food for thought, eh?
By the way, once upon a time, there was a limit to the number of files that could be stored in a single folder. It was about 500 files. Trying to save one more file resulted in lost work. Yep, not saved anywhere. Yikes.
I just checked, and my Births sub-folder has over 3700 files, and no losses. So that's a good thing, eh?