I lube my chain before every ride; I bought my C5 from the second owner, at about 1100 mi on the clock. How do you tell if you have the stock chain or if it is an aftermarket chain? And how do you tell if your sprockets are being damaged? Mine seem to look fine, but without experienced eyes who knows?
Conventional way is to lube after the ride when the chain is still warm.
Lube will easily go where it has to go and will be dry before the next ride so it will not splatter off.
Overlubing does not yield a benefit, is just a waste of money.
But lubing after a ride in the rain is good practice.
The manual has a nice picture of healthy and bad teeth.
Bad teeth look spiky and will eventually break off with a nice twang. That's a good give away.