Hello, been a while. I tag and record each connected circuit prior to disconnecting, paying attention to what amperage breaker the circuit is currently connected to. Lots of times you can find situations where #12 is used to start the circuit in existing, but later #14 is used in that circuit, and the breaker is a 15 amp existing. In those cases it is very important to connect back to a 15 amp breaker again on replacement. Taking a few photo's of the existing is sometimes a bit of help as well.
