Wear and tear vs sudden damage
Many policies draw a hard line between damage that happens gradually and damage caused by a sudden, accidental event. That line drives many outcomes.
Why insurers care about “sudden”
“Sudden” helps insurers separate unpredictable events (a burst pipe) from predictable deterioration (a long-term slow leak). The more an event looks gradual, the more likely it is to be treated as maintenance.
Discovery vs occurrence
People often discover damage long after it started. Policies often focus on when the cause occurred, not when you first noticed the symptoms.
Mixed causes
Real incidents can involve multiple causes: a sudden event plus long-term wear. In practice, insurers often try to separate what they consider “covered” from what they consider “excluded.”