Bed bugs spend most of the day in hiding. Their flat, wide bodies allow them to hide in places that are difficult to see. If you find a bed bug in the mattress piping, it will be half inside the crack, and if you find one in the floorboards or walls, it will be in an area you will never see. This makes it difficult to spot every single bed bug in a house, but you can get a general idea of the size of the infestation by observing the number of bugs.
When the light is turned on, bedbugs will eventually come out of hiding. This is because the insects spend most of their time feeding in the night, and they are less active during the day. Usually, they come out during the day only when they are threatened. If you have a large infestation, it will be easier for the bugs to come out during the day, because they are many.
If you suspect that bedbugs have infested your home, you should remove all the bedding and examine it for signs of their presence. You should also check the seams and framing of the bed. If you find any traces of these bugs, you should contact an exterminator for help. Exterminators have the right tools and knowledge to detect a bedbug infestation.