This is for sure a TL;DR post........
I learned long ago to not tell people to do what their money. It's their money, they can do as they please.
I see absolutely no advantage to having separate accounts. I have heard (a) it ain't broke don't fix it and (b) financial independence as the primary reasons for doing so. Now, I really don't find either of these as an advantage. And in fact I can detail significant disadvantages in having separate accounts.
Everyone's situation is different. I get that. I think the key thing above all else is that you and your spouse need to be on the same page with your financial goals/planning. Do you want to retire early? Do you want to drive luxury vehicles? Do you want to go on extravagant vacations while young? Do you have kids? Do you want to contribute to their higher education? Etc...etc... There is only a limited amount of funds available and you need to determine together how these funds will be distributed. If you are not on the same page it will not matter if you have joint or separate accounts or even how much you make because the funds will be limited no matter how much you make.
So let’s get back to the separate accounts. There are a ton of minor disadvantages here. First, you may be foregoing added benefits for higher account balances, be it in the manner of interest rates paid on savings, interest rates paid on loans, discounted fees for certain services available at higher balances, and so on. As a bottom line guy, these all certainly add up and it is broke, so you should fix it.
Let’s go to medium size disadvantages. You may be missing out on significant discounts available on say bundling insurance policies. And if you have separate investment accounts, you may be significantly overweight in certain investment types which can cause a big problem in the case of market correction, yield increases, and add years for you to retire because of not being properly diversified. eta - oh and multiple open accounts can lead to greater threat of identity theft, more paperwork/taxes missed/passwords. AND it can lead to someone forgetting about accounts/money. yeah, yeah, this could never happen to me. It can happen and it will happen I know plenty of people, including my grandmother who seemingly forgot about a checking account with nearly $80K in it until one of her adult children took over her finances when she fell ill. $80K!!!
But to me, the biggest disadvantages await further down the road and can rear their ugly head. These will come out when you are not both flush with cash. Maybe one of you is, and the other isn’t. Perhaps it’s job loss. Perhaps it’s an unexpected windfall. Or perhaps it’s the need to be a primary care giver to one’s sibling or parent, or niece or nephew. And one of the partners runs out of their accounts and is no longer able to properly contribute to the families costs. What was easily dealt with when funds were readily available will start with a small argument, snow ball from there.
Now as a joint account person, that is not to say me and my wife do not have our own funds. We do. We stash away money to do with what we please. Further, we each have our own credit cards. So it’s not as if it’s a purely community property. The joint account is rather to keep each other in check. All of our pay is deposited directly into the joint account and funds are dispersed from there. Knowing that my wife could possibly know I’ve taken out a bunch of money to bet on an event, probably keeps me from doing so. Conversely, having my wife know I can see if she takes out a bunch of money to buy that Coach purse she’s been eyeing probably keeps her from doing so. But, more importantly, we communicate with each other when we want to do something like that. It’s never been an issue because at the end of the day, we both have the same goals with our money in mind. It doesn’t keep me up at night wondering, worrying if my wife is going through her money too quickly on frivolous purchases or how am I going to explain that I actually spent 3x more than I said on a golf weekend with the boys. We still have financial independence to do things, we just may need to SAVE up for the big purchase instead of buying it on a whim. I know this is un-American, but I can live with that.
I could go on and on, but end of the day, I really don’t care if you all have separate or joint accounts – I just wanted to lend a hand.