All homes have some level of mold in them and not all molds are dangerous health risks to the people living in a home, but sometimes an inspector will come upon mold and recommend that a mold inspection be conducted to determine it the mold is dangerous.  For some buyers, they may have people that will be living in the house that have certain allergies to certain times of molds and they may elect to have a mold inspection regardless to assess the mold levels and risks associated to them.  Mold is generally dealt with on a case by case basis with homes so it is not an inspection that is always ordered.  If mold is found to be hazardous by a mold inspector, the solutions to mitigating the mold can anything from a very simple inexpensive process to a cost prohibitive remediation effort.  Its something to be aware of but not a road you will generally cross until you have already had the general inspection completed.