Very nice to read this topic with everyone's smart ideas! I've just started using multiple bank accounts in Bunq and for me the main purpose is to be more aware of what I spend on different things and to make more conscious choices (ie avoid impulse spending or at least be aware of how much it amounts to). I've never been any good at budgeting, I'm that type of person who can buy something every day (eg a coffee) thinking 'it's only 1.50, no big deal' and then at the end of the month be surprised at where the 45 euros went... ;-)
As I said I've just started but I'm already very happy at having separate accounts and having a plan for how to much to spend. Every month in the same day a fixed amount will be transferred and I try to stay under that but it it needs to be more, then at least I now know exactly how much I am spending. I don't separate fixed things like rent, insurance, taxes etc. But my separate accounts are for:
Groceries together with my husband
Clothing and shoes
Entertainment (books, music, films)
Eating out / coffees with friends etc ('horeca')
Unnecessary snacks / candy /chocolate
holiday travel /day trips
Money for charities
Savings
I don't mind that other expenses, eg birthday presents for family or replacement of a household item etc will come out of my main expenditures because for me the focus is on getting an overview and more grip of what I'm spending for myself on these things listed above. I'm already saving money because seeing the number in my account makes me much more hesitant to buy a coffee or candy at AH to go on the way to work, realizing how much it amounts to in a month if I am constantly buying such things. :-) so I can probably adjust my budgets after a while to transfer more money into more useful jars and less into these impulse spending accounts. :-)