Mold is a fungus that is essentially everywhere and is a required element in life. Mold growth is what helps in the decay of living material, such as fallen trees and leaves. The mold grows on this dead product and starts digesting it. Without mold, there would be all sort of natural product lying around that has not rotted.
Even though mold is a needed component in life, it is not essential within your house. In fact, mold within your house is a cause for alarm. Specifically, when you see the mold development is recurring.
Mold can cause health problems and the impact can result in long-term and permanent health conditions, so do not take mold development gently. If you constantly are tidying up mold within your home and it keeps returning, then follow the guidelines on this site to remove your issue before major health issue occur.