Comment by thomasahle

I once studied the expected remaining length of a game of chess, as a function of moves played: https://chess.stackexchange.com/questions/2506/what-is-the-a... What was interesting is that for the first 20 moves (40 half moves) the expected remaining length will decrease at a near linear rate, but then it levels off at about 25 remaining moves, and after 45 moves every move played will _increase_ the expected remaining length.

At the time it surprised me, but of course it is natural to expect long games to be long.