Since you asked: My basic bike maintenance philosophy is "as needed". Every time that I ride I make a mental note of any maintenance or changes that I want to do to that bicycle. Then I usually get it done before I ride that particular bike again.

When my chain starts to make noticeable noise, I clean the exterior by cycling it through a rag. If the chain looks extra gross, I'll dampen the rag with a little solvent of some kind. I don't worry about getting the chain absolutely pristine. Then I drip the tiniest trickle of chain lube that I can manage onto each individual link. I'm currently using Chain-L mostly because I like the guy who sells it. Then I leave it alone for awhile. Before riding again, I try to wipe all of the chain lube off of the exterior of the chain with a dry rag. The rag never really comes completely clean.

I replace chains when the distance between two rivets stretches past 12 1/16". I have no idea how many miles that equals because I don't keep track. I can tell you that the time span is in years so that's good enough for me.