Funded startups get to argue about which metrics matter. Bootstrapped companies do not have that luxury. For a company growing on its own revenue, cash flow is not one metric among many — it is the singular constraint around which every other decision organizes itself.

This is not a disadvantage. It is a forcing function.

When runway comes from a bank account rather than a wire from a VC, the question of whether a given spend is justified becomes immediate and sharp. Hiring a new engineer: does the work that person will do produce more revenue than they cost within a reasonable window? If not, the hire waits. Marketing campaign: does it convert customers at a cost that leaves margin? If not, it does not run. The feedback loop between spending and outcome is tight because it has to be.