Everyone tells early founders to raise. Almost nobody can tell them what the money is actually for, or whether they need it yet.
The defensible answer is denominated in iterations: how many honest build-measure-learn cycles does this capital buy, at what cost per cycle, and what would each cycle settle? If the answer is 'runway', that is not a plan; that is a countdown.
Sometimes the true answer is 'you don't need it yet': the next three cycles are cheap enough to fund from revenue, savings, or sweat. The cheapest capital is the cycle you didn't have to fund, and a founder who can say this out loud to an investor is more fundable, not less.