
You should be aware that the 4% rule is an older rule that has come under pressure in recent years. Following it no longer necessarily guarantees you won't run short of funds. It may work depending on how your investments perform, but you can't count on it being a sure thing, as it was developed when bond interest rates were much higher than they are now. We see this strategy mainly being used for shorter retirements where the person wants a simple plan with low flexibility
Life expectancy plays an important role in determining if this rate will be sustainable, as retirees who live longer need their portfolios to last longer, and medical costs and other expenses can increase as retirees age.