My biggest mistake went on for years. My grandmother told me her father (James H. Duffer) was named after his father, and his mother's name was Elvira (Bell). I kept checking Duffer records all over Tennessee and Arkansas looking for James and Elvira Duffer, and not finding anything - census, marriage, death - nothing. I even put enquiries up on all the then-existing genealogical websites trying to find them. Finally another Duffer researcher told me the only Duffers he had with the appropriate birthdates in Tennessee were Abner B. Duffer and his wife Malvina. I initially rejected them because I figured my grandmother must know her grandparents' names. Later on another Duffer researcher suggested them again, and also provided the names of all their children and grandchildren. I immediately recognized the names of all my grandmother's aunts and uncles, as well as her father and mother. This researcher even had my grandmother's name in his tree. Turns out, the researcher was the son of one of my grandmother's first cousins! Starting with them, I was able to take the family back to eighteenth century Virginia, as well as adding a number of additional lines. It was early on in my years of genealogy, and I learned to value information from elder relatives, but never trust it completely. Keep your mind open!