All of this is assuming you do get the upper hand (good luck) and mileage will vary state to state.
If you honestly believed your life was threatened and you had to; kill him.
If you don’t honestly believe your life was in danger, or at least isn’t any more, leave him flat on the ground or limping and dial 911.
Rules?
You are soliciting opinions so off to IMHO it goes.
If you fight (bear spray, fists, knife, gun, holy vorpal sword, DEET), you may or may not come out of the encounter without having had the shit kicked out of you, which at your age could be permanently debilitating or fatal.
If you defeat your attacker, he (if he survives you), his family, his buddies, or all of them in a pimp-mobile will get you at a later date, and kick the shit out of you and then kick the shit out of you again for good measure, which at your age . . . .
Move. Move now. Move far away.
Or just keep a few bucks in an old wallet and immediately hand it over when you are about to be mugged.
And if you insist on going outside rather than simply using 911 for a meal service, you should always bring someone along who is slower than you.
no, I just choose not to live in a shit hole where people are always assaulting me to try to take my stuff.
seriously, this “street fight” bullshit sounds like nothing more than a bunch of Internet Tough Guys fondling themselves over how they’d “handle it” when attacked by a “gang” of “thugs.” for the most part, if you’re in a situation where a gang of thugs is threatening to thump your skull, that means you are also a thug in another gang. “Street fights” are the jack-off fantasies of the meek.
Taking life advice from the Unabomber is probably a great idea. So many people just let his wisdom go to waste.
Now, what if you drop your wallet on the ground and, when the mugger bends over to pick it up…kick him hard in the head?
If he goes down, you win. If he doesn’t, now you’re dealing with a pissed off mugger.
And that’s assuming the mugger is stupid enough to bend over to pick it up, instead of requesting nicely that you do it.
“You want to fight me? How about if we just…fuck instead?”
The Zeroth rule of Fight Club. Don’t fucking join Fight Club!
PS. There actually is a zeroth rule of Thermodynamics.
A fight lasts until you can get away. If you can get away before it starts, so much the better. H2H combat training is useful if it concentrates on that.
A knife is a poor weapon for self-defense IMO. It combines the disadvantages of a gun, since it is lethal force, and the disadvantages of being unarmed, because you need to be within arm’s length to use it. Guns and Mace are preferable, providing they’re legal in your jurisdiction.
Regards,
Shodan
I’ve a book called Meditations on Violence written by Rory Miller, an experienced prison officer which deals with most aspects of fighting, the hows, the whens, the whys, it’s a good read if you want to get a no bullshit view on what happens if you get into a fight.
There’s also a ‘quick and dirty guide to not being successfully sued’, which lays out that the law grants you the ‘“minimum level of force” which you “reasonably believe” is necessary to safely resolve the situation’.
The most valuable thing in it is how to realise you’re being dragged into a violent situation, how to win before it starts as it were. Another good one on this is A Professional’s Guide to Ending Violence Quickly by Marc MacYoung, who calls the process ‘escalato’, Miler calls it the ‘monkey dance’, where typically young males will escalate the situation verbally until a haymaker is thrown.
MacYoung puts it best; "Anytime you step into the arena of physical violence, you have to accept that it may not end until you or your opponent or maybe both are dead."
A curious aside. Up in the Great White North, it’s OK to carry large size cans of pepper spray, but not the wee little cans of the stuff, which are prohibited weapons (long-gun=weapon, handgun=restricted weapon, machine gun = prohibited weapon). The rationale behind this oddity is that we don’t want urbanites using the stuff as a weapon against each other, whereas the folks in the boonies have bears, lots and lots of pesky bears, and need the stuff in cans that hold enough to deter a bear rather than make it think “Yum, pepper seasoning!”
This - IMO, in response to the OP. Your goal in a street confrontation is not to win a fight, but to escape with your health. How much you need to incapacite the confronter depends on your ability to run, how close safety is, etc.
When I used to train, I heard the acronym Escape To Gain Safety. Eyes, Throat, Groin, Shins. Tho I never was a big fan of eyes as a target (unless with spray).
Other folk joke that the best defensive style is Nike-do! 
“Pick it up!”
“No, *you *pick it up!”
“No, *you *pick it up!”
“No, *you *pick it up!”
No shit. May as well inform that “Crime Does Not Pay”, or ask them what their mother would think.
Even before reading the OP’s initial thread content, I saw two questions in the title.
Rules for Street Fights (?)
If you’re talking about two untrained idiots taking a dispute (e.g. Which is better, Spaghetti with meatballs or without?) up to a physical fight level…
Rule #1: There are no rules
Rule #2: Refer to Rule #1
The Law, of course, will see things differently. There are laws against dueling+, brawling, battery, assault (which isn’t the same as battery), brandishing, mayhem, disturbing the peace, and all sorts of ways and reasons people can and do turn disputes into fights.
When to Stop?
Assuming melee combat has started*, many previous responses have noted that The Law generally calls for minimal use of force to stop the combat. I will simply add that this seems to weigh upon law enforcers as well, since there’s a formalized review process to decide whether or not the use of force was excessive. [Much news has been made in the aftermath of those review results being made public.] Minimal defensive force is basically just enough to get out of the bad situation and no more. Can you knock the assailant away or on the ground and run? Then do so and don’t look back. The legal clashes come in response to “then why did you stick around and…” or “if he only had a [hand-weapon] why didn’t you just out-run him?”
The rest of this thread is not a whole lot different from the many dozens of previous threads [which usually come up in IMHO – and I see this one has been moved there] that are basically “What if…” speculation exercises.
A neighbor I knew long ago related to me the words of San Diego Sheriff John Duffy: Mental Masturbation
It’s an interesting and exciting exercise, but it serves no purpose except as a distraction.
Every few weeks or so my karate instructor would break from the normal lessons and show us defenses against a knife or baton or other martial arts weapon. At the end of the session a student (not always the same one) would invariably say, “That was fun! But what if the guy has a gun?”
My instructor would respond, "Good point. And what if he has a grenade – or a bomb – or a tank – or a K’tinga class battle-cruiser?
My point, my instructor’s point, my neighbor’s point, and the former Sheriff’s point is that you can do what you can with the training you have (or lack) and it will always take you only so far. After that, worrying about “What if the situation is beyond my abilities and training?” is a waste of time.
I’m not suggesting you or your concerns are a waste of our brainstorming and advisory capacities (we are blessed with a tremendous capacity for brainstorming and offering advice). I’m saying you’ll find a lot of suggestions in the responses that run the spectrum of feasible to ridiculous but you, and only you, know your abilities, strengths, weaknesses, shortcomings, et cetera and only you will be able to change or maintain the details of your life and behaviors to meet or avoid the threat you perceive.
–G!
*And, if it hasn’t started, then avoid letting it start. Regardless of who is morally/socially/politically/mathematically/whatever right, the law enforcement agents and system are harsh even when they support the winner (and it just plain sucks to be the loser).
+I saw an article in 1991 about two men in San Francisco who were convicted of violating that law. It had been passed in the mid-1800’s, partly to show that California was civilized enough to become part of the Union and partly in response to the crazy behaviors among the influx of mavericks flooding into Gold Country. The law has apparently never been repealed, just mostly-forgotten.
Its almost never one on one, the opponent(s) for the most part are usually not sober or completely sober, a fight is usually concidered a “part” of their night out. Unless they are right there, cops and witnesses are not what you want to be around after the fact.
Don’t get into the fight, if avoidable.
Don’t expect rules, they expect to get away with shit and brag about it next day, probably with video
Go time, hurt the fuckers and put them down.
Anything is a weapon, gun, make it a revolver, knife is for power jabbing, ( I think its useless).
Regardless, when you need your social piece, your not going to be carrying it, now you have to improvise
no matter what, make sure yours is the only story
Go time came and went, and you wake up in a hospital. Decision time, did you do enough to let it stand, other wise , do you remember enough about him/them to find them, and this time bring a room broom.
At your age, physical violence should never be contemplated, if your gonna be in a combat engagement, bring a weapon, its why Sam Colt made everyone equal.
Declan
Acting schizophrenic worked for two seperate guys I know menaced by drunks.
I wouldn’t have helped two other guys I know who were bashed by characters who just piled out of a car: they weren’t reacting, they just wanted to do some bashing.
Learn some jui jitsu chokes and walk away when they’re unconscious.