MINI GUIDE TO FREEING UP DISK SPACE (by a datahoarder idiot who runs on 5 gigs free space on 4 TB)
You will find more trash with the combination of 4 tools. Czkawka (duplicates and big files), Dupeguru (logs), VideoDuplicateFinder by 0x90d, and tune2fs.
VDF finds duplicates by multiple frames of a video, and with reversing frames, and you can set similarity % rate and duration of videos. It is the best tool of its kind with nothing to match it, and uses ffmpeg as backend.
There is a certain amount of disk space reserved on partitions for root or privileged processes, but users who create /home partition separately do not need this reserved space there. 5% space is reserved by default, no matter if your disk is 1 TB, 2 TB or 4 TB. To change this, use command sudo tune2fs -m N (where N is % you want to reserve, can be put to 0% for /home, but NEVER touch root, swap or others, use GParted to check which is which partition).
Regular junk cleaning on Linux can be done with BleachBit. Wipe free disk space once in 3-6 months atleast.
On Windows, use PrivaZer instead of BleachBit.
Since all of these are GUI tools (except tune2fs which requires no commandline hackerman knowledge), this guide is targeted towards tech literacy level of users who can atleast replace crack EXEs in pirated games on Windows.