In Vancouver, the frequency of roof inspections depends on the age and type of the roofing system. According to guidelines from Paragon Roofing BC and the National Roofing Contractors Association, the recommended schedules are:

1. Newer roofs (under 10 years old): These should be evaluated every two years.
2. Older roof systems: Asphalt shingle roofs older than 10 years require yearly reviews to monitor weathering and potential deterioration.
3. Seasonal timing: It is ideal to schedule assessments in the fall to prepare for winter freeze-thaw cycles and heavy rain, as well as in the spring to check for damage caused by winter storms.
4. Emergency checks: Post-storm inspections should be conducted within 24 to 48 hours after intense rain or wind events, which are common in the Vancouver region.

Regular bi-annual or annual checks help identify minor drainage issues and wear from moss accumulation, preventing them from escalating into costly water damage.