Depends on the situation, IMHO. There's a lot of literature on evaluating a tactical situation. I live in a "duty to retreat" state, so the law says I must retreat if I can do so without endangering myself or bystanders.
If they have a contact-distance weapon (knife, screwdriver, baseball bat, copy of "It Takes A Village", etc.) and are father back than about 7 yards when you complete the draw (remember the Tueller Drill), you cover them and negotiate a disengagement, as in "Florida law only allows me to shoot you in the front, so you'd better turn away and run."
If they are close enough to reach you with that contact weapon, you must fire to protect yourself. Again, Tueller taught us that 1.5 seconds of hesitation equals a knife in the gut.
If there are several agressors trying to encircle you, shoot the one in front of you and move out through the gap, then turn and cover your retreat. You can't wait in this situation because one of them will get behind you and swing that tire iron.
If they have a gun, shoot as soon as you reach point of aim. Don't try to negotiate -- people who try to get the baddie to drop the gun end up dead. When it's all over, if the dead bad guy's prints are on an unholstered gun, you have a good case for self defense.
DISCLAIMER: I am not a lawyer and this is not legal advice.