I tend to see 3 minutes as a key goal - and 4 minutes as maybe the ideal? A lot of what I write is in the 2 minute range - simplifying some pretty complex topics. In terms of views/earnings, those around 3 seem to do well. But, I also think it is context specific.

If your piece is longer than 6 minutes, the title/hook needs to be amazing. Alternatively, if you're an established incredible writer, I'll def read your longer work - but, that means you may need to have some shorter pieces to draw me in.