>>108104225To elaborate, the metaphor ''flogging or beating a dead horse'' means that an activity is *fruitless*, not that it's been repeated too many times. It refers to hitting a horse to make it pull a load-- obviously, if the horse is dead, it doesn't matter how hard you whip it, it still won't pull a carriage. The phrase only *connotes* repetition, probably from conflation with the phrase ''to be done to death'', meaning something being done until it gets stale, combined with the normal use of ''beating a dead horse''; you can only say it when you're without doubt something is fruitless-- like if it's already been fruitlessly attempted many times before.
