Oil companies love guys like you. You are throwing away a product before you get even half of what you paid for out of it. While it does "work" it is not cheap. Multiply what you do times all the other guys that do the same thing, and you are wasting millions of dollars for no good reason.
Not only are you throwing away $$$, but you are tossing a valuable resource, not to mention all of the excess waste oil you are creating. Even if you recycle that partially used oil, most recycled oil gets burned. So you're adding unnecessarily to air polution as well.
Who knows better the maintenance demands of your scoot, than the people that engineered, built, and have to stand behind it? Look in the owners manual and find what Honda suggests for oil change intervals. I'm certain that it's three or four times that 1500-2000 miles.
I'm not a tree hugger, but I hate wasting money.....or anything that still has a useful life. If you really want to take good care of your scoot, consider an UOA.
Blackstone Labs
For the cost of one oil change, a Used Oil Analysis will tell you exactly what is happening to your oil, and hence your engine.
You wouldn't buy a gallon of milk and drink half then throw the other half away because it might be bad, so why do it with your oil.