Everything that's relevant. T would be bored to tears if I tried to tell her everything and I'd be there forever.
We only discuss the topics that give me problems. Then we dig to find the root of where my reactions come from.
I don't see a need to bring up everything you've ever done simply because there is most likely a larger underlying issue that made you do some of those things. Discuss the issue not the things you did as a result. Example: I was mad so I threw an object across the room and broke it. Just discuss what made you so angry.
Maybe not a good example, but I don't necessarily share the results of my reactivity, just that I am reactive to certain triggers. At the end of all this therapy, I don't want to be so reactive any more.