1. I generally make the decision to (initially) watch a tv show because of a tv trailer or a commercial I saw.
2. Sometimes, all I need to see is one episode to not want to watch it anymore.
3, Mostly, I think it probably takes me three episodes to determine that I don't want to watch it anymore.
4. If I discover that I really like a show a lot, I will watch (every) episode for years or until the show is no longer on the air.
5. There are also shows that I might think are just okay.
The shows that I think are just okay, I don't watch every episode.
The just okay shows I can watch sometimes while missing many episodes along the way.