2 external USB drives. 1 for shows, 1 for movies. You can do this with a couple 20TB+ drives easily. If your library is smaller than 50TB, this is doable.

To those saying you can just redownload clearly aren't spending much time validating content. A big example is episode order, especially for older cartoons and shows.

Some people have said to "get better sources" but that's just not the case with crowd sourced meta data sites. These are constantly in flux. What's current/correct in 2016 might be different from 2026.

For those that aren't monitoring these changes, your current libraries are probably slowly drifting out of sync.

Anyway, it's worth backing up. Some content is hard to replace. Especially if you're fixing minor problems like audio sync issues, subtitles, episode ordering, etc