Hi John,
Same place my master leaked and it had between 8K and 9K miles on it. This is a shot in the dark but I figured my car didn't get much use from the original owner, 8200 miles in 15 yrs. I get the car and I must look like a slave driver to the those parts, 8K miles in a yr. The conclusion I draw from my experience is that too little use is no good for the hyd clutch sys. I don't have anything factual or a conclusion drawn from mechanical knowledge though. I'm just guessing. I replaced all the parts and had 8K miles of trouble free driving. I did the adding of the fluid thing from almost the time I got my car till I found the leak inside on the firewall, that was about a month of checking & adding fluid.
I figure the first time I have to add fluid I'm gonna start looking to replace all the stuff again. I still think if the car gets use the seals will remain well lubed and not get stuck from sitting??
Tom