One of the toughest things to learn in any discourse is when to terminate an exchange. I don't think it is tough because it's hard to tell when it is a good idea as much as it remains tempting to keep responding when you can think of a way to respond to something someone else has said. It's right there at the tip of your tongue (or fingers in the case of online exchanges), so why stop the exchange and when does it make sense to stop.
I've lost confidence in the traditional view of what exchanges supposedly are. The traditional view is that we exchange ideas and if we differ one party changes their mind on the spot. Even though I suspect that people who think and write about discourse know this is false, the belief that exchanges work this way still seems pervasive. This serves to explain much of the frustration we face when we engage in unproductive discussions. If we instead start seeing exchanges as an opportunity to trade ideas without the requirement of agreement, in a series of exchanges spanning an undefined amount of time, I think we can move toward more productive discussions in general.
Something to keep in mind when ending discussions is that nobody has a right to get answers from you. Demanding responses from you does not mean you need to indulge them. If people play the role of judge or inquisitor you still have a choice to carry on or not. Keeping this choice in the back of your mind can save you from a lot of grief and a lot of bad discussions that make you and your interlocutor unhappy.
With that in mind, I'd like to highlight some of my own guidelines for ending discussions to get the thought running in your mind. My guidelines are probably wrong at least to some degree, but I consider them a starting point. I don't like to write really long blog posts, so I will create small posts on each reason I use to decide when to terminate a discussion. I will try and start with the obvious ones to get them out of the way, and then try and shift to more nuanced reasons.
I will list the topics here as I complete them, so expect an incomplete list here, with the ever present possibility that more posts may be added later.
Here are the reasons I end discussions:
1. Aggressive Behaviour
5. Final Thoughts & Closing