Miles really doesn't have anything to do with it. It's on the annual maintenance checklist: front forks/rear shock absorbers oil leak inspect. I've had bikes that never ever leaked. I've had some seals that went early. It's a wear part, from what I understand.
Of course you'll need to add some fluid, but if you get the dirt out it saves you the PITA of taking the forks all the way apart and it is a good trick to know if it happens again before that much fluid is lost.
Which fork is it? As I understand it, only one fork (the right?) has any damping action. The other is only a spring. It may be the case (I don't know) that fluid is not essential in the other fork. I wonder how important the seal is on the side with no damping.