As a 22 year old female, I'll admit that when I walked home from college classes in the dark every night (walked home to my off-campus house, not a dorm nearby), I would scope things out. I didn't feel afraid though. It's hard to explain; I think part if it may be that I'm such an analytical person that I subconsciously enjoy "contingency planning" in any situation I encounter. So, if I were crossing the huge parking lot along the back edge, where there's woods and it's barely lit, I'd take notice of any other car or person, but mainly because my mind likes to wander, not because I actually perceived a threat.
I've never carried pepper spray or any type of weapon (or anything I intended to use as a weapon).
I grew up in the ghetto in a decent sized city. During the early 90s, we had a long period of violent gang wars. As a kid, my brother and I were shot in the legs and head by a well known 16 year old gang member. He was carrying some type of hand gun loaded with BBs or birdshot, so we weren't injured beyond lumps and aches. The kid was killed in the gang war. Living there, I was always afraid, always. It got worse the older I got, because I understood things like gangs, drugs, and racism. By the time we moved, I was often too afraid to play in my own yard, because kids from the brothels and crack houses would come over, steal stuff, pick on my brother, and start their own fights.
When I was 11, we moved into the house my great grandpa built. It's a smaller house and yard, but safe neighborhood. We don't even lock our backdoor during the day (only me and my parents have housekeys).
This one time in high school, my dad called the cops because one afternoon, this weird guy knocked on the front door and tried to make small talk with me. Then he asked if he could come in and take my picture. I remember memorizing every detail - he was black but had almost orangish skin, he had a large mole on his bald head, and his tie was like metallic purple. He said his name was Oscar and he carried some sort of hard case and said "well, I didn't know Miss America lived here!" I thought it wasn't a big deal; obviously I did not let him in and asked him to leave. But my dad freaked out because he thought the guy had staked me out (I was home alone from 1-5pm everyday after school).
As a college student, I tried not to be afraid of men simply because they were men, but every time I hear again that 1 in 3 women are sexually assaulted at that age, I tried to at least maintain some level of hesitation (still walk home alone, but not get into a strange guy's car, things like that).
One habbit I have is that if I'm home alone, I always lock the house doors when I'm in the shower!