Sometimes I find myself on the receiving end of what I call "wittering," or for lack of a better term verbal diarrhea. This is essentially where someone will start talking at length, often without pause, about themselves and events that have happened in their life. Upon me trying to change the subject or re-direct the conversation, they usually steer it back to wittering about themselves.
I find this especially happens with older people, and more often with older women, who tend to repeat themselves both within the same conversation and across multiple conversations.
It usually happens more with people I don't know that well.
In these situations I usually tune out and make noises that I'm pretending to be interested, then I make up some excuse and exit when I can't take any more. I can't help but feel like this is a little rude of me (then again, it's a bit rude of them to assume I want to hear all about their life and events which I have no context for), so I was wondering if there's a "nicer" way to make my exit before twenty minutes pass while I have other things to do.
Ultimately I didn't ask about their current medical problems, or their life history, or their in-laws, and I really don't care or want to hear about it; I don't know why they assume that I do. Perhaps to my detriment in these cases is that I think I'm a pretty good listener, maybe they pick up on that and exploit it.
So what would be the most effective and most polite way to exit or change the subject of these conversations into something we can both enjoy?
Some clarification:
This usually happens either in social settings or at home. For example, I live in a house-share with an older couple, and one of them will often witter unprovoked whenever they see me. I'll be coming in after work or after buying groceries, saying hello etc., and then they'll dive straight into their chosen subject of the moment.
Me: "Hey, how are you" etc.
Them: "Fine. So, my mother in law..."
One thing I try is to basically cut in and say "Sorry, I've got to (do some task or go to some appointment)" and start moving away, but this person in particular tends to keep talking, even when I'm out of the room and moving away. No matter what I do they don't seem to get the message, and will take any opportunity to talk my ear off. It's got to a point where I just avoid them now if I can, which feels unpleasant and anti-social.
Another example that I can tolerate more is when people ramble about things which are in context. For example, I'm in a walking group, and often older people will witter to me about their walking escapades, but I can kind of understand that since they're talking about something relevant, even if they do go on too much and (I think) it's clear that I'm not interested.