i made a spreadsheet of debian release dates, graphed the days between releases and calculated a probable release date based on last release date + average days between releases* +/- 1 std deviation
if i remember correctly, bookworm was within my predicted range (apr-aug 2023, i think) and we're now fully within trixie's predicted range
*before etch (4.0), release intervals varied wildly, so I don't take those into consideration