BKDave, I'm with you on taking it to 4.75V, I tell everyone to stop at 5v to be safe. Do as I say, not as I do.
Given both the voltage and the history of the battery, you can pretty much tell all the time if the battery is good or not. I've never come across any type of battery that I couldn't tell that it was good or not by the voltage.
FYI: I never check my voltage. I listen to the servos. Servos sound different when the battery is low. Not a good way to tell, but a way to tell none the less.