Up until January in the Ford and April in the Mazda, 5/0W-20 has been the only oil used.
17 year old Mazda - 244,000 km
13 year old Ford - 108,000 km
8000-10,000 km OCIs
35 year old Ford van - 153,000 km
Last 15 years, whatever oil is around (always synthetic), once every year or two...