Filters really are your engine’s first line of defence, protecting parts by keeping out unwanted debris. Any material not caught by a filter can potentially damage the engine and, at the very least, compromise its efficiency.
In many cases, filters are small and inexpensive but, in common with anything to do with regular maintenance, servicing them is vital. Each engine will come with its own schedule of how often they need to be changed, based either on running hours or the length of time since the last change.
The consequences of not changing the filter regularly are initially seen in poor engine performance and this is a progressive path. Eventually, unchanged filters will fail and the substances you have been trying to keep out of the engine will enter it, causing damage that will cost many times the sums you may have saved by not changing the filter.