Married for 6 years now, together for 9.
When we were living together, we made a joint checking account. After awhile, we retired our old single accounts. It was just too troublesome to juggle bills with all the accounts.
We "handle it" with debt. We don't spend money on buying stuff. We use money for mortgage payments, loan payments, and credit card payments. For everything else, we spend debt.
When we want to make big purchases or any purchases, we just put it on the credit card. Sometimes we are able to pay it off. Othertimes, not.
We have about 20k-25k of credit available. We could probably get more, but we've never needed it.
It's may not be the best system, but it works for us.
When we travel, or worse, travel during the holidays, we incur a lot of expenses. We can't always pay off the debt that month, so we don't worry about it. Later, in January and February, we cool it on spending while we pay off the debt.
It's a lot like dieting. We cheat on the holidays to have a good time, then we get back to our diet until we get the extra pounds back off.
As for individual purchases, I don't give a shit what my wife buys. She doesn't much care what I buy. If, when we look at the credit card bill, we see it's out of control, then we'll pay attention. We'll see that maybe that binge spending (or in the dieting metaphor, eating) was a poor idea, and we need to tighten the belt the next month.
Then after we pay off the card, we'll just go back to business as usual.
Sometimes, we'll anticipate spending in advanced, and cool off spending the month before a big spending month.
As for individual accounts, we don't have them. Sometimes we think it may be nice, but too much of a hassle for us. We're very much "roll with the punches" type of people. We try to think about it as little as possible, because we're not interested in obsessing about money. She comes from a poor family, I come from a wealthy family, and now we're living a comfortable middle class living.
As for health accounts, savings, and retirements, we put in as much as reasonable.