As your oil lubricates the engine, it picks up contaminates and carries them away. Just the way it's meant to. Deutz filters have a high relief valve pressure of 35 PSI which allows the engine to run longer between filter changes. Other filters with a relief valve setting as low as 7 PSI allow unfiltered oil to circulate through the engine much sooner. Deutz Filters are designed to supply properly filtered lube oil to the engine during a normal maintenance cycle.
Oil analysis is the best way to check frequency of oil changes needed.