A balance is a single number at a single moment. What it can support depends on what is already claimed against it: the rent due in three days, the utilities in six, the groceries that cannot wait. Recurring obligations convert a balance from a stock of money into a schedule of commitments.
Income timing matters just as much. Income expected in five days and income expected in eighteen days describe different financial realities even when the amounts are identical, because every day of waiting is a day obligations continue to fall due.
Financial context is the discipline of reading these together — obligations, timing and commitments — before interpreting any single figure. It is the foundation everything else in PFSI is built on.