I have a shed of older bikes, two of which (Suzuki GS850s) have been mine for nearly 30 years, and during the early years of ownership they were working hard. I routinely changed out the oil at 2K miles with whatever was available at the right price, avoiding the cheap cheap stuff. There is nearly always a bargain of decent make oil on clearance somewhere, so I'd just keep my eyes open for that and stockpile it when I found it. Mostly car oils, but occasionally bike specific oil if it was at the right price.
Anyway, one of those two has done nearly 150K and the other is knocking on for 300K. When I've had any of the engines apart to fix the inevitable leaks, the internal wear has been negligible.
The 300K one has just had new rings, pistons and bores were absolutely fine for another couple of decades at least.
Like others have mentioned, the 2K interval is just about right - if I can feel the gearchange getting notchy the rest of the internals are also at risk, so it's cheaper to change the oil and reset the clock.
Anyway, one of those two has done nearly 150K and the other is knocking on for 300K. When I've had any of the engines apart to fix the inevitable leaks, the internal wear has been negligible.
The 300K one has just had new rings, pistons and bores were absolutely fine for another couple of decades at least.
Like others have mentioned, the 2K interval is just about right - if I can feel the gearchange getting notchy the rest of the internals are also at risk, so it's cheaper to change the oil and reset the clock.