I'm sometimes a nervous nelly when things get a bit off kilter on my ST. I've had it for almost a year now and flushed the clutch system twice, still the fluid gets dark pretty quickly. Then I started smelling a very unique melting plastic smell and I notice my clutch fluid was a tad low. I quickly ordered a new CSC and gasket...
The replacement took me about 2.5 hours at my usual slow and steady pace. I had it on the side stand most of the time (lacking a motorcycle jack). At least 1/2 hour of that was spent on bleeding the system after installation. Hardest part for me was removing the old gasket. Everything else seemed to go smoothly. Larry talked me through an extra bleed step at the MC and things seem nice and smooth. The source of the smell was a rubber channel laying on the exhaust that I couldn't see till the Tupperware was removed - LOL. I still think it was good to replace the CSC as you can see in the pictures below.
The ugliest part wasn't really from leaky brake fluid. It appears to be a bit of sludge from the oily pushrod and some water intrusion past the gasket that mineralized over time. I pulled apart the CSC and could see evidence of wear and some corrosion from water in the fluid. The new one does seem more smooth, but then my bike goes faster when I polish it too FWIW & YMMV.