The specific 4% Rule was actually coined a few years prior by financial advisor William Bengen. The Trinity Study is famous because it provided the academic backing for Bengen's assertion.
They found that a 4% withdrawal rate had a 95% success rate over a 30-year retirement period using a 50/50 stock/bond portfolio.
Instead of 4%, the 2021 Morningstar study calculated that a safe withdrawal rate for a 30-year retirement is closer to 3.3% to 3.7%, depending on your asset allocation.
Given the Morningstar research on lower forward-looking returns, do you think 4% is still too aggressive for my specific plan?