Ever since I was old enough to leave the yard without someone holding my hand, I have been a target for and victim of assaults.
A few situations were avoidable with wiser choices on my part, but most were not. There was a brief time when I tried not fighting back. It didn't work out so well: they would beat on me for awhile and stop when they got winded.
Fighting back, before I trained martial arts, had mixed results.
When I first started martial arts about 15 years ago (that decision being made following an assault by three men during which my jaw was shattered and three teeth knocked out by a tire tool), I studied bar fights for a couple of years.
Of all the places I've lived, the Missouri Bootheel seems to have the highest number of simple assaults. Most of the Bootheel assaults I've seen do not involve weapons, are not related to a robbery or any other secondary crime motive, and very often end up involving multiple attackers. Alcohol is almost always a factor.
Attackers are usually males 18-25 years old, maybe 18-30.
The people who initiate assaults around here tend to be what some would call "accomplished street brawlers." While they aren't exactly trained fighters, they are usually somewhat more experienced in fighting than your average person who tries to avoid trouble.
These attackers typically have skills which range from "look tough but really can't fight too well" to "can and will put you in the hospital unless they decide to stop or somebody intervenes."
When it comes to self-defense, a martial artist should first seek to avoid the situation and look for an opportunity for escape if unable to avoid it. Only after these measures are taken should martial art techniques be applied to enable an escape.
It is important to self defense to train with intensity, always mindful of the possibility that you just might have to defend yourself someday with the techniques you are practicing. Heavy bag work and some medium or even heavy contact sparring are, in my opinion, very important as well.
After years of studying and training in taekwondo and hapkido, I no longer worry about being assaulted. A big part of that is making efforts to stay aware of what is going on around me so I am not caught unprepared.
On the very few occasions that I have been assaulted since I started training, the attackers have regretted picking me for their assault. There is always the possibility that I could be assaulted by a person or group in the future that can overcome me despite my training, but my chances have definitely improved.
Even if there were no other benefits to studying martial arts -- and there are plenty -- improving my ability to defend myself has made all the time and effort of training well worth it.