Ok, I'm going to give the unpopular, but factual, opinion.
The only reason for changing oil every year (or as specified in the manual) is for maintaining warranty. Once outside warranty, you only need
to change your oil when your oil needs
to be changed, and 6 months (or one year) has nothing to do with that. If not oil would come with an expiration date on the bottle and significantly shorter shelf life.
And don't get me wrong. I've got my own maintenance fetish, it just doesn't include unnecessary oil changes. In europe no one ever thinks of changing their oil less than once a year. When I came back to the States I couldn't believe that 3 months is the norm. It's just plain wasteful. Oil technology has advanced ridiculously since then. I personally tailor my oil change schedule to the vehicle and usage scenario (and religiously log and monitor it via Acar app. That apps worth gold), so in the bike it's about 1 year or 12k miles. And even I know that's out of personal vanity and a "feel good" feeling, not an actual need.
For every other vehicle, or in case of doubt, I do what any fact and reality minded user would do (rather than asking strangers on the interwebs
), I do an oil analysis. While this is pretty standard in the aeronautic industry, it never caught on to the automotive industry. Probably since it would annihilate the JiffyLubes in a moment. Basically, I buy a few oil analysis kits
for about 15$ shipped, analysis included, and before changing my oil I take a sample. I send it to the lab and they check all the variables that your engine would ever care about
: Water %, Coolant, all the additives, all the contaminants, all the metals, etc. Along with graphs to compliment. The real number you care about is the Base Number. Basically that indicates how much of the additive package is left. Once that number is out of spec or close to that, you need to change the oil. If it's within spec, there just isn't enough of a reason to change the oil. That's the hard truth.
As a personal experiment, I've been doing oil analysis on a Toyota prius ever 3-6 months to see when I actually have to change the oil, and the vehicle had done 15K miles and 2 years and a half and the oil is still perfectly good. While oil certainly deteriorates and gets acidic with age, modern oil simply has good enough additives to cope with regular use and low mileage over long time periods. That is, as long as the vehicle gets some use with some regularity (enough to evaporate any condensated water in the oil), you oil should be good for at least 1.5-2 years.
Just don't take my word for it, or anyone else's for that matter. For 15 bucks find out exactly how often you have to change your oil, on your specific bike, and your specific usage pattern.