Beginning genealogists may be tempted to focus only on their own direct line, ignoring records from siblings of their ancestors. This can lead to missed information. The death certificate of my great-great-grandfather, John Michael Trautvetter indicates he and his parents were born in Saxony. That is very specific and very helpful (grin). The clip on the right is from his brother George's death certificate. George's record provides exact places of birth for George and his parents.
Of course this is secondary information, but it still is a valuable clue and would have been overlooked if I had only focused on "my line."