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here we go!! this was the question that killed the mayan's, and started world war 1 and 2!
the manufacturers interval is called a 'recommended interval' for a reason. if you desire to keep the vehicle warranty, it's the maximum amount of time you can ever go between oil changes.
otherwise, things like used oil analysis like at
https://www.blackstone-labs.com/ are what you need to send some of your old oil off to decipher what's happening within the motor. that will give a better indication of if you're changing it too often or too late, as well as offer some indicators on your overall motor health.
i'm on the 3k-5k mile oil change schedule. at 3k i buy the oil. 4k, i start thinking of which weekend i want to change it. then i finally change it around 5k.