re: What’s more accurate - recommended mileage or maintenance minder?

full synthetic gets changed once a year or every 10k miles (its good for up to 15k miles)

semi synthetic gets changed twice a year or every 5k miles (its good for up to 8k miles)

regular oil gets changed every 3 months or every 3k miles (its good for up to 5k miles)

time means nothing and is a much less accurate measure of oil life, go by your miles driven which is the most accurate way