[MerelyMortal]

10-11 minutes seems to be the optimal length to maximize ad impressions.

So whener I see a video that is 10-11 minutes long, I assume that is the reason.

Knowing that, it is a lot easier to recognize "filler content" in these videos (content that could easily be cut out or shortened without reducing the quality, or content that if cut out, would improve the quality)

[bravetraveler]

This is very likely nonsense (I'm not a creator or know any well), but I believe monetization starts around the ten minute marker

If the video is suspiciously close to that and a fairly 'hot' topic (likely to garner clicks), I immediately become suspicious that the video is there for ad revenue and little else

[sudosysgen]

It's not just ad impresssions. Your video at that time would be shown to many more people if it was of around that duration.