The pop machine at work charges $1.50 for a bottle of pop. Recently I was getting an oil change for my car and decided to get a pop from their machine. I put in 6 quarters and one wasn't accepted. I put in the 6th quarter 6 times before I realized this machine charged $1.25 and I didn't need the 6th quarter.
As your research moves to a new location, new time period, or new family, are you changing your assumptions about records, laws, and available materials? Pay attention when your research moves to a new area and don't assume everything is the same.
It probably isn't.