Oddly, Im better at it than my INTJ (though he has no qualms doing it when it aint his own funds - like the funds for his company). Perhaps this is an Si vs Se thing?

I grew up in a family that wasn't that wealthy and with a mother who was...well, a witch with money. She made every dime count 5 times, somehow
And so, making a budget when I had an allowance was an..almost natural thing. While Im perfectly capable of blowing 5000 dollars in minutes, I'm also capable of not spending *any* money, until I have money available to me again. And I automatically allocate certain amounts to certain areas in my life. It used to be gifts and things I could buy at the mall, nowadays it's food, rent, bills, cats and personal treats. It aint that different, tbh
My INTJ otoh grew up in a family that had plenty and is so used to having money - also coz he's never had an issue making any, that's more my...problem

- that he resents having to make a budget as he feels he should be able to buy what he wants, when he wants, with the exception of really big ticket items - like a house. It's like a matter of pride to him, so he doesn't like looking at his account and allocating stuff. I've suggested more than once to give me his accounts and I'll do the rest for him, for this very reason
He is not as bad as he once was on this front though as he knows budgeting is on occasion definitely the smart thing to do.