Pepper spray is a tool you can use in escelation of force but not something I would want to soley rely on. Anybody that has seen the law enforcement use of force module, first step for the officer's response to a suspects actions and the risk perceptions they present are verbal controls. Next step are the contact controls like wrist locks and hand roation techniques. Moving up the scale when the subject becomes assaultive and likely to cause bodily harm, you come to compliance techniques that inolve a little more pain to the suspect such as baton restraining techniques, nuero-muscular controls and this is also the level where your pepper spray would come into play. Moving up another notch is where you start using an ASP or PR-24 striking movements, and tasers. Finally you come to the subjects actions are presenting a lethal threat that can cause death or seriously bodily harm. It's when things get to this level that you have to consider using deadly force to terminate the subjects actions. To think of this in an example, if you are looking at getting hit by an attacker with bare hands, short of this guy being Bruce Lee or the like, you could probably use pepper spray without being accused of using excessive force. I mean, you can't just up and shoot a guy for slapping you or something and not get in deep doo-doo over it. However, lets say you do use that pepper spray, you find out that it doesn't work and now the actor is pulling out a knife or gun and coming at you. Now you've crossed that line into those actions that are lethal threat perceptions with the actor intending serious bodily harm or even killing you. Now you would be justified in dropping that pepper spray and resorting to using deadly force. If you ever get a chance to see a "use of force" module, you get a better understanding of what actions you can take in response to an attackers actions without resorting to excessive force being used when it's not warranted. So now you get an idea of how pepper spray can play a part in your overall layered defense by giving you a less-than lethal option should you need it but at the same time, I wouldn't consider it to be the end-all solution either. Carrying pepper spray in addition to a firearm is always a wise idea.