Two phases, modelled separately: the years you contribute and the years you draw down. The result is not just a balance at retirement but the monthly income that balance actually sustains for the rest of your life - and, if your target is higher than that, the year the money would run out.
Lower than the historical average, and lower again once you are drawing down. A broad equity portfolio has returned roughly 7% real over long periods, but a retiree holding bonds alongside equities should assume less. The safer habit is to enter a real rate - after inflation - so the result is in today's money.
The largest monthly withdrawal that leaves the balance at exactly zero at the end of your horizon. It is the arithmetic answer, not a safe-withdrawal recommendation: it assumes a constant return, which real markets do not deliver.
A constant-rate projection hides sequence risk. Two portfolios with identical average returns end very differently if one has poor years early in retirement, because withdrawals lock in those losses. Treat any single projection as a central case and stress-test it by lowering the drawdown rate.