A fast sustainability check for a single pot of money. Enter what you'll have when you stop earning, the return you expect it to make, and how much you'll draw — Plumb Line shows whether it lasts, grows, or runs aground, and in which year. No accounts, no imports; just the question, answered.
Deterministic monthly-compounded drawdown — it compounds a steady average return and excludes volatility and sequence-of-returns risk (a poor run of early years depletes a pot faster than a smooth average suggests). A "sustains" verdict means it passes the first test on average, not that it's guaranteed. For thinking, not a forecast.