Son Pacho,
Choose to toggle the timer carefully depending on WHERE you are playing. Ex: Will you most likely fight illusive missile cavs like the horse archers of the steppes then I´d defenitely recomend leaving the timer on. Otherwise you´ll be chasing them for hours. If you on the other hand have theese kind of cavs I´d defenitely leave the timer on. (Numidian miss cavs are also tricky)