Use a certified or licensed inspector and have them take small samples (with the homeowners permission) to be tested. That really is the only way to be sure. Usually if the asbestos is contained, like in floor tile and its in good shape your may be advised to leave it alone. On the other hand if the pipes in the basement are covered with what generally looks like asbestos and its falling off and in bad shape, then you might be advised to have it removed professionally. Once removed an air quality test is performed.