An popular TCMA slogan is Zhi Ge Zhi Wu - Martial means stopping spears (i.e. ending the fight). Actual combat, unlike sport, generally lacks a set of rules defining the end point of the conflict, so the concept of finishing is a bit more ambiguous. It is my feeling that finishing a fight cannot be reduced purely to physical destruction, because excessive use of force often seems to provoke an escalation of the conflict into wider social spheres. But I am not really sure how to incorporate this thought into practice...

So, I am curious what kinds of perspectives on the idea of finishing exist within the Chinese martial triaditions (or Chinese martial culture more generally). Can anyone suggest a Traditional perspective on answers to the following questions:

When is a fight finished?
How can you tell?
Are there practical ways to improve your control of this? What are they?

Any thoughts on the matter will be appreciated.

A fight is over when those who were fighting, say against you, no longer have the will or capacity to fight (against you). Generally combat (as in warring or dueling) can be very decisive; with few exceptions, the dead are no longer combatants (yet not necessarily without some combat use for those still living).
Here are some examples: (1) U.S. Marine patrol, Pacific Theatre, WWII ambushed by Japanese soldiers with fixed bayonets (spears if you will); a Marine private wounded at the onset grabbed a shovel killed one, his sergeant killed three with a knife, & so on: they killed all of the ambushers (they stopped the spears); THAT FIGHT WAS OVER (whether or not the will was gone, the capacity was); (2) earlier in that war a Marine machine-gunner was killed during a night banzai attack; nevertheless, his finger remained squeezing the trigger, so he wasn't yet out of the fight (here the will to fight may have been gone, but the capacity wasn't); (3) that war ended in surrender (so while the capacity to carry on the fighting was still present, the will was deminishing).
You can't always know when a fight is over; and one that's over may rekindle later (shortly, or after a long respite). Some attorneys in suits & some judges in robes walk this earth thinking they know the answers to your questions, but they don't (that doesn't stop them from stomping all over you with so-called legal proceedings...a possible extension of a fight, eh?).