William Bernstein states with impressive historical evidence, that if you want your retirement money to last as long as you will (and you might live a lot longer than you think) then you shouldn’t plan on withdrawing more than 4% per year.
 
He discusses this in his book, The Four Pillars of Investing, on pages 229-240.  Financial advisors purporting that you can withdraw up to 8% per year don’t know what they’re talking about.  If you tried this stunt in 1965, you would have been dumpster diving by 1977.
 
I like to call it “the 4% rule” and I plan my future investment withdrawals accordingly.
 
One of my favorite blogs outlining this with further academic support is this one:  Bylo Selhi