I read those articles and, coupled with a few minutes to spare, was inspired to download my own earnings history and create a spreadsheet to calculate my benefit if I stopped after this year, along with some other data. I have 33 years of earnings history right now, most of it reasonably well compensated, so I'm firmly in the 15% bracket of "returns" on further work. Here are some notable facts:
My "projected benefit at Full Retirement Age" (assuming I continue at the same salary until age 67 and start receiving benefits then (17 more years):
$2706. This is the number on the annual SS benefits statement, in today's dollars.
My calculated benefit at 67 if I quit working now, based on my work history to date, in today's dollars:
$2415.
I'd have to work 17 more years at $100k+ per year to get $291/mo. in benefits. No thanks! I'm planning to continue working for about 5 more years (for other reasons!) and these years will result in about $35/mo. gains thanks to replacing some early years that were zero or close to zero. After that it gets even worse..
I like the summary in RoG's article; make sure you have 40 quarters and can fill up the total earnings to the first bend point at 90%, which is currently $359k. Not that much, and after that, the "ROI" is lousy.