I'm not sure how variable this is, but I've definitely experienced unwatchable levels of ads (mostly on mobile/Android). Having an ad before you even know if th

I'm not sure how variable this is, but I've definitely experienced unwatchable levels of ads (mostly on mobile/Android). Having an ad before you even know if the content has interest is already a challenge (eg a how to video), and most that I see are in the 5-15sec range before watching and every 5-10min after that. However, I have had a dual 30sec ad before starting a video that repeated every 2min on something I actually wanted to watch, but quickly stopped, because it was "unwatchable". I consider that level to be at about 10% of watch time (regular TV is about 25% 8/30 min in larger blocks).