This was the least surprising result. I thought "combined finances, with an allowance" was basically the default for married couples who have been together a long time and/or since they were fairly young. Currently my wife and I just contribute an equal amount to a joint account for the mortgage and car, and the rest is basically "I've got it" in a proportional sense. It basically works because we spend less than we…
Of course, most couples in my social circle are extremely wealthy by non-Bay Area standards, so that gives people a lot less direct incentive to be especially thrifty.
My parents, and my marriage, have a different system: we ask ourselves about every purchase if it’s likely to bring us as much joy as we feel the money is worth, and just don’t buy that much stuff because most things don’t seem like they’d bring us enough joy to be worth the outlay.
Then, when we want something expensive, and say “yes, a new couch will bring me joy even if it doesn’t bring you much joy”, we don’t worry about the cost all that much.
But having a non-scarcity mentality about this sort of thing is obviously a super privileged position to be in. When my father remarried, he tried this system with my stepmother and she... spent all their money on frivolities they couldn’t afford, and now he’s retired and barely has any savings.
So I don’t really recommend this system unless you and your partner have reasonably similar utility functions.