My suggestion is to cover your anticipated expenses with safe investments. I use ladders of CD's, Treasuries and Series I bonds totaling approximately 30X annual expenses. Any income produced is my inflation adjustment.
Am I understanding you correctly? 30x annual expenses in VERY safe money vehicles? Do you mean the 'necessary' expenses or all annual expenses? If say a couple has $60k/year, it's almost $2M in cash and bonds. Of course, I'm not retired and I'm either not that conservative or I am missing something in your post.