[skrebbel]

FWIW My SO and me are the only people I know who do the allowance thing. My friends routinely talk about "he/she spent so and so much on $USELESS_ITEM, grumble grumble". I say "pocket money!" and they nod and laugh and don't do it because it makes them feel like children.

[burfog]

Doesn't that encourage waste? You seem to have decided that a certain portion of income will just be blown on random stuff.

I go with double-approval. You could call it a veto system. Both must agree before spending.

There is pre-approval for unavoidable expenses like bills, groceries, fuel, emergencies, and tolls.

[zrail]

You have to decide on your priorities. Accepting a certain amount of “waste” in exchange for happy spouses is a worthwhile trade for many couples, including my wife and me.