YouTube is known for having "Good Standing" Accounts to have unlimited length. (Meaning you could make a freaking movie if you wanted and easily present it.) However, despite this, there are people online who can only stand a video being a certain length before they want to stop for whatever reason.
I, myself, have a limit of which I can handle a video being a certain length, unless it's a freaking movie or something.
My current limit is up to 30 minutes. Otherwise, it mainly has to do with the limit of time I have to watch something before I have to do something in real life.
To be honest, when something is an hour long, I prefer it to be in parts. It's rather convenient for me.
What about you guys? What's your video length limit for watching online videos?