The cast-steel clutch slave cylinder is a very common wear item that fails long before the master, and low-mileage seldom-driven cars actually see more clutch/master failures; minor undercarriage leaks usually trace to the rear main seal (fix during a clutch job) or the slave, both cheap DIY items.
Clutch hydraulics and oil leaks (slave, master, rear main)
Mazda MX-5 Miata (NA) · mechanical