4TB megadrives? How do you use up 2000GB?
Really my idea of a "megadrive" doesn't involve TBs.
But as to the question, I've been keeping stuff since I started computing around '95.
Plus I've had like 8 computers over that period of time. 3 of which are currently active.
I couldn't count how many people I've helped because I had some old program version from before
they started charging or limiting features... or some old DOS tool like Norton Commander around.
I do a bunch of stuff with Photoshop... make movie theater sized posters. One of those can eat 400~700MB a pop.
Mostly I use externals and a tiny little old 38GB drive in my laptop.... so there ya go.
If I had the power for games, I'd need even more space... probably another TB at least.