A reasonable rule is to stop just far enough behind the car ahead of you that you are able to see the bottom of their rear wheels. Anything more invites some other jack@$$ to try and fill in the gap. Anything less invites a bumper touch when traffic gets moving again.
I’ll try that.
Too many drivers do not leave gaps like they should and too many do not scan far enough down the road ahead of them.
Rant done.
I follow that rule & it has served me well. The extra space is just enough to pull out from behind a stalled car, or one where the driver doesn’t turn on his left-turn signal until after you pull in behind him. That has often saved a bit of time, and a lot of aggravation.