Name spelling variations in family history

Here's another example of the difficulty with name spellings.

Here we have William Henry Burger (with a U) celebrating the 61st anniversary of his wedding to... whom? When she wrote her own name, it was Mary Ann Dufner Burger. Here she's Maryanna Duffner. Numerous family notes spell her maiden name with two Fs, but got the Mary Ann right. Perhaps nobody thought it mattered since she was married now anyway.

Here's another document, a handwritten note that was taped into the Burger family bible, written by Frances Taylor Burger, my grandmother and the daughter-in-law of the two in the anniversary clipping:

My mother Maryanna Burger Root spent her early childhood under the same roof as William Henry and Mary Ann Burger. They split their 4-room farmhouse down the middle when their son Frank married Frances Taylor Allen (who already had a young daughter from a previous marriage), and they all shared the house. Frances was a nurse and took care of the elder Burgers until their deaths.