I’ve been a reader of mystery series for decades longer than I’ve been a writer of one. There are now four books in the Bernadette “Bernie” O’Dea mystery series, with a fifth one on the way. I don’t remember ever looking up, or doing much research, on how to handle information from previous books in a series when writing. I already understood the balance from a lifetime of reading mystery series. of mystery series books, my brain socked away my reader preferences.