D­u­p­l­i­c­a­t­e­F­i­l­e­s­D­e­l­e­t­e­r is a simple, but effective tool to locate duplicate files in one or more selected search paths. It scans the files and compares them based on Byte for Byte Comparison, which ensures 100% accuracy. You can then choose to delete the selected duplicate or original files. The program is multi-threaded and performs scans quickly.

I have a 120 GB SSD primary drive, and it contains Windows and all applications, and AppData and such, but that's it.
 
There is a Location tab on your user library folders, and I have all of mine relocated to one of several 2 TB 7,200 drives to keep my primary drive clean.  (scook uses a 'link' of some sort to relocate his - you could PM him if interested in that approach, either one works fine).
 
All Sonar content and projects, sample libraries, and all Cakewalk Command Center download files/folders all live on on of the non-SSD drives as well.
 
As a result of the above, my SSD never gets above 40 % full or so, and is just not an issue.
 
I also regularly clean out temp files and such, so things don't really build up.
 
I hope that is of some help :)
 
Bob Bone
 

From a "duplicate" standpoint, duplicates on a single drive are highly unlikely and are normally created by a user copying files to other locations. Typically backup media will contain duplicates over anything else, especially if the user changed (main) folder structure or file locations between backups.
 
From a space perspective, a simple check for a drive is using Windows Explorer, selecting the drive, and click the search box in the upper right. Selecting "Size" and going through "Gigantic (>128MB)" and a second pass on "Huge (16-128MB)" will often give insight on offenders. Temporary directories for audio/video programs are a big one to watch because of the size of these data files, but most also allow assignment of this directory in the stand-alone version of the software (e.g., Melodyne). Download folders, and temporary directories are another (also covered above in BobF's post).

I just ran Disk Cleanup as indicated above by BobF and freed up another 16.9GB!  A whole chunk of that was system update log files of all things.

[duplicate]

mettelus
From a space perspective, a simple check for a drive is using Windows Explorer, selecting the drive, and click the search box in the upper right. Selecting "Size" and going through "Gigantic (>128MB)" and a second pass on "Huge (16-128MB)" will often give insight on offenders. 

Or if you are willing to wait a bit WinDirStat, a free utility will draw you a beautiful picture of the mess.
https://windirstat.info/