...Never? By the time the earth blows up and we all die (~7.5 billion years), they still won't be done and this won't be a concern.
Step-by-step explanation:
Isn't this like half-life..... since we're dividing by 2 each day, there will be an infinitely small fraction of work left after infinite days. Wouldn't it be great if we just didn't procrastinate and finish work all at once :C
