Sorry! forgot to mention. Look up " Circumstantial evidence ".The more pieces to the puzzle you have , the better the odds that you can make a conclusion of being correct or incorrect. Or that the possiblity is likely to be True or False. Genealogy is just that unless you obtain hard evidence or enough Circumstantial evidence. Your best chances is following your Surname. When it finds a dead end, basically your Tree is finished. Example: I am not a Crandall, but lets say for argument I am a Hubbard. Therefore, should only trace the Hubbard name not Crandall name. Let's indicate the Elizabeth Hubbard married Thomas Crandall, well my roots should stop /end at Elizabeth as the last Hubbard. Making Elizabeth Hubbard of course the daughter of Mr.xxx Hubbard and Mrs.xxx(NEE)* Hubbard. For Direct lineage you should follow the MALE only. So for many people in todays World because of OverPopulation Growth, only a very small percentage of people will be able to go further than possibly 7 Generations (giving a wild guess) and Less than 1 percent able to go more than 12 Generations. Not sure about China and other countries as heard that 1st child should be Male, if not they kill the female child and try again for a Son. Implying that in China the Surname would go many many many generations.
* nee = unknown Maiden name.
By going by my previous message, indicating my proven ancestor, my 4th Great Grandfather, which is my Mother's 3rd Great Grandfather doesn't really apply to me cause I do not hold the same last name (surname)and cannot actually claim that I am 7th Generation. Using my last name, because my father knows very little about his Dad (my Grandfather is deceased) makes me 3rd Generation unlikely to make a Finding past 4 gens. So my Family Tree stops at 3 Generations. The research I am doing is just for fun.
A few years ago at Christmas, my Father-In-Law took a picture of his mother and my children. He implied 4th Generations. Because my children do not hold the same surname, they are not 4th Generation. Only way for that to be true is if the children were by his Son. Male to Male to Male, etc. My children only apply to my side of the family ..not his ( my wife's father or mother).unfortunately I only have Daughters. Therefore, my surname will cease along my Roots.