I just recently hit 35k miles on the odometer of my Model 3. I do have my second trip meter locked in for the Lifetime power usage of the car, and this is where most other people will pull the number from, multiply it by how cheap their home charging kWh price is, take nothing else into account and give a rough electricity cost. That doesn’t give the entire story though.
With the wider release of the 2019.24.4 firmware update, Tesla seems to have changed how leaving your car plugged in behaves.
In my very limited 2 days of observation so far, the new 2019.24.4 behavior keeps the car at your desired charge limit even hours after charging completes. To achieve this, more functions seem to run off wall power, one such being the cabin overheat protection.