Roaches are resilient creatures. Due to evolution, they can consume almost anything. There are techniques you can use to get rid of these bugs without calling an exterminator. The first step to getting rid of roaches is to find out where they live.
Most roaches live in dark and damp locations, usually out of reach.
The next step would be to try to seal the area or put boric acid around the areas see them coming from. When they come from outside, seal all the entrances. Place boric acid around others areas you see them coming from. Roaches clean themselves a lot. By walking in the boric acid, they automatically get some on them.