With regards to your recent marine oil filter tests (see PS July 2019, Marine Oil Filter Comparison Test), having spent my career in the aeronautical engine technical field specializing in maintenance I must state my allegiance to non-encapsulated filters and independent housings. This trend towards spin-on filter assemblies prevents in my opinion the most important aspect of filter maintenance which is particle inspection. Filters are not removed so you can inspect or replace them, they are removed so you can ascertain your engines condition. This practice seems to have been set aside to make way to quick and easy maintenance using spin-on filters. Oil analysis is fine but it should start with a simple sediment inspection after a low cost electro- sonic cleaning in a 60 Hz bath (jewelry cleaner bath).