Ran mine down to "10 miles to empty" and put in 49 litres once. Judged that to tie in with 55 litre capacity and showing remarkable accuracy of both gauge and miles to go readout. I would definitely be worried when 0 to empty came up.
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone