Oil change and filter every 5k miles or six months. What if one only drive 4k - 5k per year. I know the old argument about moisture forming in the engine and oil - or is is self preservation for the auto industry. Why would that same moisture not be a problem in oil storage vessels of whatever kind? How about a tighter engine. We all know how oil spoils like milk in just a few days - . Or is it cooling water and oil that mixes like in certain GM products. Just how picky about the exact mileage and day may Toyota be? To my reasoning - it makes sense if oil changes etc. is mileage based more than time based. If it takes somebody two years for 5000 miles so be it.
It used to be "Lube and Oil Change" and the only question was "new filter". The lube part is apparently gone - is it no longer needed anywhere? Part of this service was to check ALL fluid levels and visually inspect everything from belts to hoses clamps etc. and dust off the air filter or replace if needed.
Now - if I'm not mistaken this oil change amounts to remove drain plug, replace filter, dump in 5 quarts and collect a fee. j