If you don’t follow the minimum recommended oil change intervals, you may have to defend yourself if there is an otherwise warranty covered engine problem. That is, you may have the burden of proving that your failure to change the oil, as recommended, did not cause the problem. This would be very hard to do if it can be argued that the problem was at all lubrication related. You can, of course, change the oil more frequently without warranty coverage being an issue.
If you want to know how your oil is doing, you can have it analyzed. You take a sample, either at a change or from the crankcase via a tube put down the filler pipe, and send it to a laboratory which sends back a report. One lab that is well thought of is Blackstone--
www.blackstone-labs.com. This is what their web site introduction says: "Oil analysis can identify any problems developing in your engine long before they cause you an expensive headache. Or maybe you'd just like to get a good look at the microscopic wear your engine is producing. Can you run a fill of oil longer than 3000 miles? Are your oil and air filters doing a good job? We can answer these questions and more when you submit a sample of your engine oil for analysis" Their standard test is about $22.
My guess is that if you had reports showing that your oil was fine and did not need to be changed, you would have the proof needed to establish that not following the change interval was the cause of the engine problem.
I am new to the HiHy so I have no idea of how hard the ICE works, but it is high compression. I am thinking about using synthetic oil with the 5k change interval, the engine should be well protected and it may help with milage.