On the other hand, according to the US census, as of 2016 the number of households with 7 or more family members is 1.27% while the number of households with 1 family member is 28.13%. If we take into account the households with 3 or fewer family members we are talking over 75% of the US.

I think it is completely reasonable not to consider your circumstance when giving general advice. The vast majority of people can choose a much simpler solution because they have much simpler problems. It's interesting to hear what people in your situation need to do, but I wouldn't expect many people to relate because they have no such experience.

I agree with you, but you are using the wrong numbers.

Sure, only 23% of households have 4+ members, but they contain 44% of all Americans. Likewise, the 1.3% of households with 7+ members contain 6.2% of Americans.

And there are more people in households of 6+ members than in single-member households.

  #people_in_household  %_of_households  %_of_people
  1                     28%              11%
  2                     34%              27%
  3                     15%              18%
  4                     13%              20%
  5                      6%              12%
  6                      2.2%             5.3%
  7+                     1.3%             6.2%

Collapsed to your categories:

  #people_in_household  %_of_households  %_of_people
  1-3                   77%              56%
  4-6                   21%              38%
  7+                     1.3%             6.2%

(source: https://www.census.gov/data/tables/2016/demo/families/cps-20... where tables C1 and A1 give a total 2016 population of 318579k. Table H1 gives numbers of households with 1-6 members, which, by multiplication, hold 298913k people. The remaining 19666k people must be in 7+ member households. This matches table AVG1's 2.53 people/household and surprisingly implies that the 1.6M households with 7+ people contain 12 people on average.)

And how about the purchasing power of a family of 1?

Is the purchasing power of a family of 5 (2 adults, 3 children) any higher than someone living alone, specifically when talking about purchasing home appliances?

I mean occasionally my wife and I will both purchase bread on the way home resulting in us having a lot of bread, but I can't think of a time we both accidentally bought a refrigerator or oven on the same weekend.

Well, a decent chunk of people living alone are probably renting, so that changes the whole appliance-purchasing dynamics already, but to directly answer your question - yes? The increasingly common dual income family has more income than a single person, and furthermore benefits from the ability to share certain costs efficiently - how would that not result in higher purchasing power?

Statistics for disposable income by family size is hard to get (I don't think the US census measures that). My gut feeling is that dual income, no kids families are going to be at the very top because not only are kids incredibly expensive, but not having kids means that you can concentrate on work. Having said that, family size will also skew around age so it's really hard to say. I'll just say that I've never met a family with kids that isn't concerned about money.

But even having more money, will people buy robot appliances? Again, my gut feeling is that singles are actually more likely to buy things like that because the downside of making an ineffective purchase is dramatically lower.

A family with any kids such that you're going through the bedtime routine after dinner, then exhausted and forget/avoid the dishes.

I know that my parents started making me do dishes around age 8 or 9, and I guess I hadn't really considered if that was normal or not until now. Is it normal?

It's normal. My parents didn't have a dishwasher until I moved out, so I was made to do it or help. Before remotes I also had to get up and turn the channel for my dad. All these time saving devices really help kids the most ;)

I don't know if it's normal, but I was washing dishes at a similar age and later cooking for the family as a teenager.

My children are 3 and 5 which is why they're not much help with washing/drying and why the bedtime routine is more involved - bath, drying, brushing teeth, packing up, reading, answering questions about why they have to go to bed, why it's still light outside, how they are actually tired and so on.

Tru dat. I just left my oldest's room, everyone is asleep... walked right past the dishes to get to the computer....

With a family of 7 you're likely to have at least 1 or 2 kids old enough to be your robot for pocket money.

It's hard enough getting them to fill/empty the dishwhasher, let alone wash things until they're clean without breaking them.

Plus even our ten-year-old dishwasher is more energy efficient than hand-washing. It's more than paid for itself by now.

They’ll pocket money alright

This.

I didn't mind doing laundry when I lived by myself.

Then I started living with my wife. She has laundry preferences (among other things) different from mine (whoa!).

Then we had a kid. And another. And another. Not a family of 7, but I think I know where you're coming from. It was a walk in the park, individually. A complete non-issue.