Ten years ago when we had a office with Sat internet, a plasma TV, halogen lights and spent too much time inside working we had to run the generator two hours in the evening when cooking and one hour in the morning when making coffee. This was with a 750AH battery bank and a sorry inverter/changedr that would only charge at 70 amps, not the rated 100.
Today with all LED, no office and smart phones plus a residential refer with it's own 500AH battery bank and a 100 amp charger that actually works generator time is cut in half and only in the evening.