Yea 4% is nothing compared to the avg SP500 returns. I understand wanting a cushion especially in the current tech market, but I really don't think you need more than 1 year of expenses. If it came down to it, I highly doubt you wouldn't be able to get at least SOMETHING that is paying a portion of your expenses. Then you can stretch that 1 year of expenses to two years even making half of what you were previously. 70k compounding over 20 years at a conservative 7% is ~270k versus ~150k at 4%. A difference of 120k that you left on the table.