I'm a debt counsellor.
I start with a blank piece of squared paper
We write down all the income in one column, then all the essential monthly outgoings in another (this includes housing, insurance if paid monthly, utilities, essential contracts, set debt repayments etc).
We then make a list of all the other monthly expenses, so food, entertainment, streaming services.
We make a list of debts other than mortgage.
Finally a list of less than monthly costs, so insurance paid annually, car tax, clothing, presents. We divide the total by 12 to apportion it.
I then do the maths with the client.
It's that final list that seems to really make people struggle, keeping money back for less frequent expenses, they then overspend instead then need to borrow starting a spiral.
Renegotiating debts is actually not that common, once people have a clear written budget they stick to it, and I'm really pleased for them when I hear that they are now ok.
Op you can do the same for yourself, then arrange a saving amount to come out the day after pay day