I think regardless of intervals and what is considered to be "throwing mone away" the point is that engines age. Its crazy to assume that since the recommended oil change interval is X miles that you should only go in at that point to change your oil, for the life of the vehicle
Parts wear. They wear out, they wear thin, they deteriorate, they end up requiring new oil sooner than the manual calls for. I use synthetic in the speed, change every 3-4k, but I check the dipstick probably 3 or 4 times between changes to see how much oil I have, and its consistency. I don't change every 5k (which I believ is recommended) because I don't like how it starts smelling like gasoline. Burden of charged engines, plenty more blowby than NA
Sure, I could get an oil analysis. I could also go check my cholesterol levels with my doctor every couple months or just keep eating my fruits and vegetables
Btw, I get exactly 18mpg in the city and 23mpg on the highway, just like the window sticker told me I would get