Cockroaches have a different activity rhythm than that of humans. They are the guys who like to come out and crawl when it is most quiet. During daytime, the chances are less but possible to find cockroaches walking in groups.
There has also been this notion that they usually move away from the light because light to them is a hint that their hideout is no longer a secret and that it can be reached by humans. Long story short, they prefer to be least disturbed and therefore they seldom come out when lights are ON or when we are around.
So, while they are normally found when lights are turned OFF for a long time, you can find them at any time of the day as long as it is quiet and there are not disturbances in that place.
Based on their specific activity rhythm, they mostly remain inactive at daytime and become active at night after which they keep searching for food for hours. A little queit surrounding which also have some moisture is what they prefer. And night time, with all the lights turned off, does satisfy their requirement.
They usually choose places like the bathroom, kitchen sinks or sewer pipelines as their habitat because these places are comparatively moist and friendly to them. When they are in their hideouts, for example, in that small opening between the wall and the tiles, they try to touch their upper and lower part of the body to the surface of wall and tile to keep them warm and comfortable. Interesting enough?
Now, the question may arise as to how they manage to come out at night or in dark and still be able to see. A research on Cockroaches, as reported by 'Scientific American' hints that Cockroaches have night vision. They can see when it is dark by accumulating the light of daytime.
I hope it helps.
"Your value does not decrease based on someone's inability to see your worth"