What a great topic. There will be a lot of venting here. I have gr-gr grandpa William C. Davis, born between 1851 and 1854 in Princeton, New Jersey (so he says!). I have him on church records when he is conditionally baptised 4 days before his wedding, in 1874. I have him in the 1880 census and 1900 census with his family in Orange, NJ. His wife Bridget (Delia) dies in 1906 and is buried at St. John's, Orange, NJ. No hide nor hair of Willie. We have done paid searches in Princeton for pre-1874 stuff and we can't find him definitively. And after 1900, he has disappeared. And he isn't buried with Bridget.
I also have two of another gr-gr grandfather's brothers, who I have no idea what happened to them. Michael Hayes, born Ireland about 1845, came with parents to England. The family settled in Staffordshire (for one generation). The youngest, George Hayes, b. 1865 in Huntington, is also missing. They are both gone from the 1881 census and that's that. I might have a lead on Michael but it is proving hard to confirm. Apparently, my gg grandfather, James, never spoke of Michael or George, only his other two siblings, Mary Jane (died when she was 15) and John (moved to Australia and we are in touch with his descendants). I wonder if there was a falling out
Kath