Umm... Thanks to Ancestry.com and me being able to meet and gain wisdom from my great-grandmother growing up, I can go a few generations back, depending on which side of the family you talking about.
I don't know much about my dad's side past my great-grandparent's and one set of great-great grands' names . However, on my mother's side, my grandfather's mother knew both of my mother's family tree. It helped that my great-grandmothers were friends before they both had kids. I think the highest I got was great-great-great grandparents.
I will say, though, that DNA testing on that app can cause some great or some damaging finds. I discovered 2 of my aunts on there on accident. I don't get on their often, but the things I have found... eye opening. But I think it's worth it.