1 TB is definitely not enough, but 20 TB should be plenty. Just get about 13 2 TB drives.
You aren't storing anything useful on that I can guarantee it.
What are you storing if I may ask?
I have a ton of tv shows, movies, music, and about 100 GB just of photos I've taken from my various travels. Every time I want some new tv shows or anything, I have to debate what I'm never going to watch again. 1 TB is a lot, but it's not enough in the scheme of things.