“a zero-based budget is one where your total income minus your total expenses equals $0. In other words, it forces you to assign every dollar of income to an expense (or savings) category.”
In my opinion, a zero-based budget is simply a fancy name for a budget.
In other words, most people who have a budget simply allot any positive cash flow to a savings account or slush fund that is used to pay for any unexpected expenses. If they have a negative cash flow then they need to trim their expenses so that their cash flow is either zero or positive. For really dire situations, drastically cutting back on extras like cable, cell phone, extra groceries, eating out, entertainment, etc., may be called for.
The main thing is to have a budget in the first place.