I've purchased two new cars this year and would like to see twenty years out of both. My wife has a Honda CRV (4 cylinder) that recommends 0-20, and mine is a Toyota Tacoma (6 cylinder, 4.0 L) that recommends 5-30. Both these vehicles will get severe service for the next year and a half until we retire, and consequentially I change the oil in both at about 3k on the clock. I go through a lot of motor oil at various prices and availability. My question is...can I settle on one viscosity that would satisfy the requirements of both engines? I've been using Mobil1 in both and unless I get better advice, I'd like to stay with that. Thanks much.