Have you ever been following your male ancestor in the census, and suddenly discovered that his wife did not age the same 10 years that your ancestor did?

It could be that your ancestor’s first wife died, and he remarried someone with the same first name. And, he could have had children by the 2nd wife before the next census. So, don’t assume that the information given to the census taker was incorrect. It could be that it is necessary to look for another marriage – your ancestor’s 2nd wife this time!