Been doing this for several years and prefer this method. I also try to reduce the number of times I use a particular security question. However, I don't think the problem comes from what questions you use or what answers you provide. It becomes like others have pointed out, a problem of what a hacker can get away with answering when asked by a phone representative. Although, I do think this approach provides a little more security than just answering the "what city were you born in" question with the correct answer on every site.