I can manage the shopping alone. You ____ come with me.
Are those just the same thing? I mean it sounds natural if I interchange each of those, but let's see the example from my book:
Everything will be OK. You needn't worry. (It is not necessary)
Everything was OK. You needn't have worried. (you worried, but it was not necessary)
Does that mean needn't have is used when something is done and needn't is used when something is going to happen or what?
What about don't have to?
And consider about this:
You ______ anymore. Which one should I put? "will" and "was/were" are not mentioned. In this case I don't know if the thing is going to happen or has happened.