Yes, if the moisture source was never fixed. Mold is a symptom. Moisture is the disease. A job that removes visible growth but leaves the slow leak, the failed grading, the attic ventilation problem, is temporary by definition, and this is the usual story behind cheap remediation quotes: the price was low because the scope stopped at making it look clean.
Done right, remediation ends with the moisture corrected and the area verified, which is why Nonstop Restoration finishes every job with clearance checks and prevention recommendations instead of just a wiped-down wall. After that it is maintenance: humidity under about 50 percent, bathroom and kitchen ventilation, leaks handled within a day or two, and a seasonal glance at window sills and basement corners, especially through Calgary’s freeze-thaw winters.