How far is a good question. I repressed much of what happened to me. I asked questions of my mother and my sister. I went to various places. I googled family trees, obituaries. I went to land records of the county where the farm was. I located the property on county land maps, and was able to identify the property on google maps and satelite pictures. I learned that my dad molested my sister, an aunt, an uncle and yes, me. I always thought that I had never met my dad. Turns out that I had been brought over for regular weekend visits. I did remember him but I didn't realize who he was. I identified a pastor who molested me. I have stopped digging at this point because I can't handle what I have now found.
I have found a board certified trauma specialist who is giving me the tools to deal with things. Once I have that in place, there are a lot more people to contact and get information from. I eventually have to get this all out because I am sick of not knowing what was done to me. But I have to stop for now.
In short, the answer to that question is as unique as the person.
God grant me
The Serenity to accept the things I cannot change,
The Courage to change the things I can,
And the Wisdom to know the difference.