I say keep doing what you're doing. Oil doesn't go bad, and the filter will last a long time sitting in oil. There's a chemical rule of thumb that every 10 degrees rise in temperature doubles the reaction rate. Let's assume 10F instead of 10C (which it really is). If your oil filter temp is 190F operating and 100F resting, it breaks down 2^9=512 times slower sitting there than while operating. Basically, if your filter is quality it should last many years (decades?) just sitting there. It's probably better coated in oil than sitting on the shelf, where oxygen can get to it and cause the filter fibers to oxidize.
I've done two year oil changes (10-13k miles) and the only time the filter didn't look normal was when I used an el cheapo from Rock Auto. Everything was still intact, but it didn't inspire confidence, so I've been buying the 12 dollar filters again, $6/yr ain't bad.
Just change the oil and filter in both cars at the 5 year mark. Try to run them at least 30 minutes every month to get the engine up to normal running temperature to evaporate some of the volatiles that gets sucked into the oil, e.g, gasoline, acids, water, etc.
I have a 2010 civic with 47k miles. Bought it in 2013 with 7k miles. The paint has faded and gone to crap (thanks honda) but I keep it very well maintained. 3k mile oil changes. Function over form I say.