I change oil & oil filter whenever the odometer hits 5k and I do the valves and sync the carbs every 10k so Otto is due an oil and oil filter change, plus valves and carb sync in just over 1000 miles when he hits 200k miles. I will also be changing the Final drive oil and checking/cleaning/replacing the air filter as needed. The Final Drive oil gets done every 20k miles as well as a new air filter. The 5k-10k-20k is easier to remember than 6k miles oil & filter and 18k miles Final drive oil that are the recommended service intervals. Valve clearance checks every 6k and carb sync every 3k are overkill IMHO.
In the winter, if I'm not riding regularly, then I start the motor at least once every 2 weeks and once warmed up I let it idle until the fans kick on. That keeps everything in decent condition. The bike is always connected to a battery tender when not being ridden. We don't have super cold winters here so I generally ride at least once every other weekend or so through the winter.
If you want to be super cautious, then change it annually, but I think yer wasting perfectly good oil.