a lot of people are adamant about changing oil every 3000 miles but most Consumer oriented research information sites that have no bias toward any oil companies will tell you changing at 6K is just fine and they see no benefit to the consumer changing oil every 3000 miles. Just go with the book your bike came with and you will be fine.
The benefit depends on just how worn you want your machine to be as the mile pile up. Aside from breaking down over time and being mechanically chewed up the oil collects soot, metal particles, clutch dust, and unburned gasoline. All of which cause the engine to wear faster than it would if it were to get clean oil more frequently.
Two nearly identical bikes on the lot, same price, same mileage, same color, same accessories, no differences whatsoever except for one owner stayed on top of maintenance and serviced 1,000 miles before (and has the receipts to prove it), while the other did all maintenance at or slightly after the recommended intervals and freely admits he went 5,000 miles between oil changes because he used a high quality synthetic.....Which one are you going to plunk your hard earned cash on?
There are very good reasons to change the oil and flush the crankcase (why does nobody recommend or at the least mention this!?!?) at at the very least the recommended intervals.
1. Fresh oil isn't filled with crap and a flushed case has less crap lingering in it.
I use 1 quart of kerosene...one of the best degunkers there is and it's fairly cheap...add it to the oil with the engine cold, idle the bike for a few minutes, pull the cork...if you're really particular about particulate recork, dump an additional quart in, have a smoke, grab a coffee, enjoy the coffee. After you finish your coffee rock the bike to slosh the kero around and pull the cork...go enjoy another smoke and more coffee...give the bike a few more rocks to be sure the case is empty, recork, swap out the filter for a fresh one, fill the case with a nice heavy synthetic and 10% Lucas or similar at recommended amount for wet clutches. Definitely hand tighten only for the filter...for removal I use an old serpentine belt from my ford.
2. Oil breaks down over time, with use, and collects unburned fuel (and water which is why you're supposed to change it after a long storage) which thins it and reduces it's ability to properly cushion and lubricate parts.
The point of changing oil before it is completely crudded up and has significantly broken down is to ensure that the engine always has oil that is as clean, thick, and slippery as it can be to keep it from wearing as fast as it will with used oil. The less crap circulating in the case the less engine wear, the thicker and slickerier the oil the less the engine will wear.
A note on thicker...thicker oil causes a slight decrease in fuel economy and HP...BUT cushions gears, bearings, tappets, timing chains, cam lobes, and valve stems far better than thin oil (say 20/50 vs 10/30). It also comes up to pressure faster and maintains pressure better at idle. It does however have the drawback of making the engine a little stubborn to turn over when it's cold outside. Replacing 1 quart with 10/40 fixes that issue though.
A third good reason to keep on top of the oil is to prevent corrosion caused by the water, burned fuel byproducts and unburned fuel. Especially with today's ethanol added fuels! Ethanol is corrosive, as are the compounds of burned fuel mixed with water. The longer these remain in the case the more damage they do.
Another thing to bear in mind is it is not in the best interest of vehicle manufacturers*to have machines that last beyond the second owner without need for major repairs.
The first owner needs to be kept happy for on average a couple years until he's ready for new bigger and better.
The second owner is a potential new customer provided they're happy with their experience with the machine.
The third pretty much expects that at some point he will have problems with an older, out of warranty, and higher mileage machine.
Machines that make it past the third owner do not benefit the manufacturer much beyond repair parts and creating a reputation of durability.
A major downside for he manufacturer is that overly reliable machines that last well beyond the warranty tend to be held on to longer resulting in reduced new vehicle sales....Notable example the cars made by Honda and Subaru...both have a reputation of being just "broke in" at over 100,000 miles showing....great for the used car buyer, not so great for the manufacturer's new car sales.
Look up planned obsolescence
A good thing to keep in mind is, you can easily and cheaply prevent wear, but the only way to repair it is to replace the worn parts...Which is neither cheap nor easy.