Many years...many miles...many (good-running) vehicles...I've developed a system over the decades, and applied it to both bikes and trucks. I change my oil according to the vehicle odometer. In the days when I used carbon-based oils, every 2500 miles on the odometer (X,000, X2,500, X5,000, X7,500) I change both the oil and filter with high-quality lubricants--the Consumer Reports scientists evaluate Valvoline to be the best, and that works for me. But a number of other brands are also highly rated.
Now that synthetic lubricants have become readily available, I run them exclusively, but I allow 5000 miles between oil changes. I focus on the quality of the products I use, and now that my racing (and hellraising) days are over, my vehicles hold up extremely well using my system. I have also learned that synthetics are vastly superior to carbon-based oils in every possible respect, and definitely worth the extra cash. Enough said?