Endings

So I guess I've never really thought about how I've never ended an RP before without someone leaving first. I've always RPed in the past with one other person and we'd keep going on until one of us just got tired of the same old thing over and over again. I'm sitting here and thinking about each individual RP and I can't really wrap my mind around any endings. So I ask anyone interested in reading this: How do you come up with your endings? Do you think of them ahead of time or just casually find a way for it all to end? I know a good idea would be to discuss it with my partner but I was just curious as to when all of you literate folks out there began concocting ideas in the course of your writings. Thanks much!

Most of my RPs haven't been played straight to the end, so I can't really help you out there. LOL