As a follow up to this post reviewing 6 tools to view and analyze disk usage and this post on TreeSize here is review of SpaceSniffer. It is described by its author as

SpaceSniffer is a freeWare (or, better, donationWare) and portable tool application that gives you an idea of how folders and files are structured [...]

As a followup to my post on TreeSize here are some other downloads I have come across that let the user view or visualize space usage on a disk.
For this article I chose to analyze a folder that is approximately 945MB and has 28 subfolders and 170 files. Using a not so new Windows [...]

TreeSize is a small executable that lets the user visualize how much space a drive or a folder and its subfolders is taking. Opening the program and opening any directory or folder presents a windows explorer like and expandable list of folders.
The results can be viewed in KB, MB, GB, or even mixed units so [...]