I bought my 2002 LS650 new May 2002. I keep it in my garage except when I ride to work. The bike has 7300 miles on it. The milage is light because I ride a short distance to work and run local errands. I've done some work on it to get better sound and performance. I use Amsoil Motorcycle 10w-40, changed every 1500 miles with filter. If I don't make 1500 miles, I change the oil every year instead.
I have observed no degradation in performance, no leaks, no oil consumption, no final drive problems, no brake problems, no electrical problems. I've had to replace the original tires. The bike lives in Central Florida and ridden all year.
I'm really impressed with the reliability of this bike.
I believe the bike will go happily by the 25,000 miles without major maintenance.
Keep good records, inspect/maintain your machine often, and use excellent lubricants.
I suspect Savage_Greg puts 25,000 miles on his machine every year, so he has to do major maintenance more often than most of us.