Some plumbing problems should not wait.
Stop using affected fixtures and call when sewage is backing up, a tank is actively leaking, water is reaching electrical equipment, a supply leak will not stop, or you smell gas. If gas may be present, leave the area first and contact the appropriate emergency service or utility from a safe location.
For non-emergency issues, early attention still matters. A slow drain, intermittent pressure loss, damp cabinet, rusty hot water, or unexplained increase in water use often costs less to address before it becomes a shutdown or property-damage event.