Last 28 days my average view duration was 3:15, but some of my videos are long and others are short so it's hard to tell what that means. My average percent watched could use some improving, it's only 27.4% in the last 28 days. That said it ends up translating to about 1.3 million minutes watched, so it's not like your retention can't suck and still get you views and watchtime. I have a video that got 2,000 views over the last 48 hours and has been doing well for a while with 92% like ratio, and it only has 23% retention, so it continues to get suggested despite that. I don't know what that means, but I think better retention would help my view to sub ratio so I should probably clean it up haha.