How many hours should a single player game today be to warrant a sixty dollar purchase?

[BHR-3]

i rarely purchase games at $60 theres always deals where you can get em for $40 or less

im fine with SP that are 8-12hrs long, now with achievements and all i usually get 20-40 hrs per game b/c im ocd and want to 100% or get as many achievements as i can per game

i think that a SP shouldnt have more than a 12hr long story unless its really a epic game/story like GTAs RE4 and mgs solid games, if its a average or mediocre story/game i dont want it to keep going on an on