While it may be rather obvious, how frequently you need to run the generator or otherwise charge the batteries is directly dependent on how much electricity you use and how large a capacity the battery bank is.
There are many RVs that can go for a lot longer than half a day (and not just high-end or fancy units). The water heater control board, and fridge control board (for an absorption fridge), and propane/CO detectors don't use that much power. If one is judicious about lights and entertainment power usage, it's not unreasonable to expect at least a few days from a fairly modest battery bank in good shape.
With two golf cart batteries and no solar, I can generally go two or three days in cool weather (where the furnace is used at least at night) and somewhat more in warmer weather where the furnace is not used. I definitely do not need to run the generator twice a day.
If one has a residential fridge, that uses a lot more electric power than an absorption fridge.