My 2 cents-Rotella T6 synthetic 5W-40 in the diesel, Mobil 1 synthetic 0W-20 in the Miata, 10W-30 whatever in the old F150. 5,000 mile intervals. The Sportster gets straight 50 weight, changed in spring and fall, regardless of mileage.
Oil is cheap (and it does get recycled) compared to parts and $80 an hour shop rates. Suit yourself.
Was not intended to be an "oil thread", more of a "Big Brother" thread as another example of government intrusion in our lives.