A leak is a leak. If your master is leaking, no matter how little, it is leaking. Not good.
Slaves on these cars are crap. They need to be replaced fairly frequently from my experience. I consider them a wear item personally (like belts, hoses, fuel filter, etc). I would be happy to only replace a slave every "couple of years." Point being, chances are yours is on its way out. Have you checked the boot to see if it's leaking? If you haven't replaced it in a couple of years, I'd be kind of shocked to hear that it's not.