Exactly. 

Treesize is great.  It showed my 760-gig hard drive to be about 300 gigs of video.

I therefore moved the entire video collection to an external hard drive, and now Pinnacle Export shows "60 per cent full." 

Treesize also shows the status of my four, yes four,  external hard drives.  Each of them contains that same 300 gigs of videos. Backup overkill

Say, why do my multi-terrabyte drives fill up over the years?  Spam? Invasion from Pluto? Nefarious Russkies? 

Nah, it's just those automatic backups, in my case weekly backups of everything.

All but recent ones can be deleted. The backup program can be configured to save only the last few, which is all required. 

Yes, I know the world is in the cloud and I am hardware.

But my recent 4T Seagate external drive is the size of a smartphone and cost less than  $90.

Since I work on one fixed computer in one office, physical backup is all I need.

And no monthly fee. 

Oh, and then there's Vimeo. I have 150 videos stored there. It costs about $100/year.  All can be downloaded at will with no loss.  All can be shared or viewed by public. 

Vimeo is a quiet place. YouTube is for public display. 

Here's  "Philosophy of Sailing: Solo to Hawaii and Return". All my stuff is edited with Pinnacle.  

https://youtu.be/z5m9yT06Khg?list=LLS6qLhh5YBeL42HRMh3dc1A