Obviously, there are many approaches. I’ll describe what we do and why we think it is successful.
I have seen many couples having disagreements and even divorce over money; it seems that this is a typical reason to fight and sometimes fight badly. The realization is that different people have different preferences what to spend their money on, and if you are not rich, it continuously leads to disagreements - ‘did you really need another pair of shoes?’, etc.
Our solution is a weekly allowance. First, all our money goes into one pot and is considered equal. Many couples find that a difficult step, but I never thought twice about it - I trust my spouse, and I share my life with her, so why not my money?
From this, we agree on an ‘allowance’ that is used to cover any non-common cost; this includes all clothing, dining out, buying things, etc. The amount was chosen to match about what we spent for those things anyway, and then adjusted annually.
The main point is that there is no critique allowed about what this is spent on - you can blow it all on shoes, or buy books, or wine and dine, or gamble it away, whatever. We are doing this since 23 years now, and we are very happy with the results; we never have financial ‘fights’ anymore.
Disadvantages are the effort - you need to keep track of it somehow. Either you use a separate credit card, or hand it out in cash, or have a complete accounting (I do the latter, because I want to).
Regarding all other spend, we use the accounting to plan ahead for at least a year on all cost and income that are expected, and that shows us the available cash flow and where it might get tight. It also shows you where the money goes, and where you could cut if cutting is needed (or wanted). Again, there is some effort in collecting the data, but it is worth it (for us).