For a 90% chance of success with a 30-year retirement, the most recent data show 4% as the safe initial withdrawal, if you use a static (but adjusting for inflation) draw.

However, the Guardrails Approach allows over 5% safe initial draw. You just have to be able and willing to trim your draw by 10% if your calculated draw exceeds your target (e.g., 5%) by 20% (i.e., 6%). On the flip side, if your portfolio soars and your calculated draw would be 20% below target, you increase the draw by 10%.