I appreciate the answers. I have seen enough of the unreliability of some peoples trees to not trust them implicitly. This is the current issue I am wondering about:
I am a probable descendant of Michael Spencer. Would you please evaluate my evidence?
Sarah Spencer is my 3rd great grandmother. I have ample sources establishing that. My Sarah Spencer was born in 1800 in Kentucky (American Genealogical-Biographical Index (AGBI)). She married Samuel Wilson in 1823 in Greene, Ohio, USA (Ohio, County Marriage Records, 1774-1993). At some point before 1850 they moved to Montgomery, Indiana, USA, where both she and Samuel are buried. (1850 & 1860 census records and Find a Grave).
Find a Grave said that her father was Michael Spencer, born in 1762 in Rhode Island (which I realize may not be the correct location), and who died 1 Nov 1828 in Ohio. I am usually pretty skeptical about the accuracy of such info, but I used that as a spring board.
I found a Michael Spencer living in Washington Kentucky in 1800 (Kentucky, Tax Lists, 1799-1801). So that particular Michel Spencer could be Sarah's father. In 1807 there is a Michael Spencer living in Greene, Ohio (Ohio, Compiled Census and Census Substitutes Index, 1790-1890). Could this be the same one that was in Kentucky in 1800? Maybe...
So, then I came across the WILL of a Michael Spencer who died in Darke County, Ohio in 1828. First off, I see that this Michael couldn't have died 1 Nov 1828 because his will was written on 7 Nov 1828 and probated 24 Dec 1828. Well, the headstone, if there was one, was probably not in great condition, so it could have said 11 Nov, or 1 Dec... or something. The will names wife, Mary, sons Francis and Thomas W., and daughters Sarah, Delilah and Ann. This sounds promising.
Back at Find a Grave I see that other Spencer's in Spencer cemetery include a Francis Spencer and a Delilah Spencer! Now I'm really intrigued. But how can I know if the Sarah in this will is my Sarah? I was at a loss. Then I happened to look at my Ancestry.com ThruLines for Michael Spencer. I found that I have 5 DNA connections to Delilah Spencer and 13 to Francis. It also shows 4 to James Spencer. (I don't think James was Michael's son, but either a brother of Michael's or perhaps a nephew, since although he was one of the executors, he is not mentioned in any other regard.)
So, my big question is, considering all the other evidence I have outlined above, can I consider the ThruLines as valid confirmation of the relationship?