For me, I'm not so much scare of creepy crawlies as I am paranoid about them touching me. And I like to qualify my fear by usually explaining that it's not so much fear as being startled. Most of the time, when I see a particularly big spider, I will try to avoid it or take it outside. If it's small, I leave it be. The exception to this is like when I go to my aunt and uncle's house where in the summer, there are SO many spiders. And these particular ones are ugly/creepy because they look hairless and their...ass part (don't remember what it's called) looks big and bloated disproportionate to the rest of their bodies and it makes me think of pictures I've seen of ticks that were full of blood. I had to go get something from a shed on their property once and when I looked out the window it was covered in layers of web and I saw like twelve of these spiders, which gets to my second rule. If there is a swarm of them, if the means is available to me, I will kill the shit out of them. Because then it doesn't startle me anymore, it's just fear, and often irrational fear of solitary creatures ganging up on me.
For instance, one of my old apartments had an ant problem and I couldn't figure out where they were getting in. But when I saw one ant, I knew there would be a shitload more, so I would always kill them. Earwigs? Those little fuckers have bitten me on several occasions, and when I find one, say taking a lawn mower out of a shed, I find a LOT of them usually. My new apartment seems to have a few centipedes/silver fish (the lighting is bad and I can't tell the coloring usually) and with centipedes, I just kill because I never felt like looking up which ones are deadly to humans and just err on the side of caution. Also, one time when they were doing this dumb ass construction project on the town square, there were these giant halogen lamps that were like stadium lighting that they left on at night for NO FUCKING REASON for months and months while they finished the project. And it attracted praying mantises. And seeing one of two occasionally would have been fine, but there were some nights where I would be hanging at my friend's apartment adjacent to the square and just going up the stairs and to the car, we would see like three scattered around the sidewalk, two on his car, and then like three more just hanging around the deserted street. We would shoo them if they were in the way, but sometimes they would fly at us an it would freak me out, so I would kill them if they did that.
As for cockroaches, I would here all the horror stories and sayings and urban legends and would never bother to research what was true, so I would just kill them if I saw them.
Reptiles don't freak me out, as I had a lot of exposure to them when I was young. Rodents kind of freak me out, but again, I imagine swarms of them. Also, I've heard them movie through walls in houses and that was unsettling.