Join Date: Sep 2018
Location: Central Indiana
Motorcycle: 2018 Suzuki GSX-R 750, 2003 Kawasaki ZX-9R, 2001 Kawasaki ZX-6R & KX250 Motarded
I change it every time I blow a fork seal, which is usually around once a year. You will be shocked how nasty the fluid is when you dump it. Excess bearing material in the oil means you should consider changing the bushings.
It gets about the same attention as auto tranny fluid in cars, nobody ever changes it until there is a problem.
Front brake fluid should be changed often as well.