I found this retirement calculator interesting from the stand point of its ability to give the user an opportunity to include Social Security at different ages. In fact, I used the calculator to enter nothing (no retirement savings) to see what SS only would provide at different ages. I'm sure just an average, but still useful.
I also found that the impact your investing styles (Conservative to Aggressive) in both "average markets" and "poor markets" illuminating. It appears using a Aggressive investing style is about 15% more detrimental (you'll be able to withdrawal about 15% less) in a poor market when compared to the conservative investor, yet is only about 2% more beneficial than being conservative positioned in average markets. Markets are anything but average in the short term, but these comparisons seems helpful. Put another way, can a retiree tolerate 15% less income in poor markets for the opportunity to withdraw 2% more in average markets. Historically that extra 2 % happens about 66% of the time (using the S&P 500 as a reference).
Over the last 30 years aggressively investing in the S&P500 an investor (retiree) would have experienced 11 years of "poor market returns" or roughly 33% of the time. Only once where they consecutive "poor" years (3 years from 2000-2002) .
Taking 15% less from one portfolio for 3 years would have been one strategy. Having that 15% (do your own math) in cash- like reserves would be another strategy. Aggressive investors needs to be more strategic when faced with poor returns (sequence of return risk) to remain the course and so one can match the withdrawal rate of a conservative investor in poor markets.
Anyway I found this calculator interesting and worth passing along:ready-set-retire-8-deadlines-you-need-to-know