You bring up whatever you feel is relevant or that you want to share. In my therapy very little if anything is ever spoken about my past. I went to address a specific life event and the effects it would have going forward and we've stuck with that focus. I can bring anything up at anytime and some things will come up, but it's not the focus. I've already been in treatment so with some issues I feel like I've been there, done that. There are things that would be useful for insight but they can be addressed if and when you see fit.