Just changed out 0W20 RGT after 5,000 miles on my Tundra. The oil was definitely dark and looked used and I put some very easy miles on the truck. There is some old-school Ti 0W20 Kendall GT-1 Max in there now but I do have about 8 quarts 0W20 Mobil EP to use at some point. Hmmm....decisions, decisons....