Intake filter replacement is not decided by operating hours alone. Dust concentration, work intensity, filter construction and intake restriction all change the actual load.
Read the restriction trend
Where the machine provides an intake restriction indicator, judge the trend rather than a single reading. A sudden change in the rate of rise often points to a change in dust load or sealing condition.
Check the seal and mounting face
Filter failures are sometimes caused by an unseated gasket, a distorted end cap or dust on the mounting face rather than the media itself. Check these during replacement.
Do not replace service with high-pressure blow-off
High-pressure air can distort pleats or damage the media unless the filter is explicitly cleanable. For disposable structures, replacement to the maintenance requirement is more reliable.