[rob]

I would be interested in knowing as well. I've been watching YouTube since it first came out and can't remember any times where I saw something I thought I needed to actually download and save in case I wanted it in 10 years. 10,000+ videos is a lot of videos to just seemingly save.

[ndriscoll]

Whether something is worth downloading is a good heuristic for whether it's worth watching in the first place. e.g. university lectures, technical talks, hobby technique tutorials, etc. are something you may want to reference in the future, or you may want to save for your kids in case they're interested in it one day, etc. The latest slop from professional "content creators" that you can't imagine keeping so you can pass it down one day? Not worth your time today either.