While I'm on the subject, I changed a circuit in my house (the GFCI circuit that runs into all the bathrooms and the garage) from backstab connections to pigtailed connections.
Prior to doing that, I measured the voltage drop across the circuit with a hairdryer plugged into the last outlet on the chain on high.
After I was done, I measured it again with the hairdryer on high. The voltage was about 2-3 volts higher.
