The dishwasher case comes down to: period between meals; and capex/storage for duplicating crockery and kitchen utensils. So I would say there is a threshold ar

The dishwasher case comes down to: period between meals; and capex/storage for duplicating crockery and kitchen utensils. So I would say there is a threshold around 3 hours, 1 hour good, 5 hours bad. It is also a factor of volume, so 1 person unnecessary, 4 person family (or whatever they call it these days), probably essential.