Concerning futility

Concerning futility
You’re wasting your time.
You’re wasting your energy.
You’re wasting your effort.
It doesn’t stand a chance.
It doesn’t stand a chance in hell. (mildly vulgar)
There’s not a chance in hell.(mildly vulgar)
It doesn’t stand a snowball’s chance in hell. (mildly vulgar)
When hell freezes over. (mildly vulgar)
You’re spinning your wheels.(informal)
 You’re (just) running around in circles.
 You’re beating a dead horse. (informal)
beating a dead horse = trying to activate or motivate something  that is finished
It isn’t worth beating your brains out (for).(informal)
It’s like looking for a needle in a haystack. (cliché)
It’s fit for the junkyard.
It’s headed for the junk heap, (informal)