re: When to begin taking social security payments

Assuming the person is no longer working, a frank assessment of health and life expectancy is in order upon early eligibility. The other factor to consider is that the higher the base amount, the more raw dollars will be available on the boost, so the A/B analysis must be done to determine the payback period if the person waits and probably should be done year-by-year until 70, actually, particularly if the 401k can support that.

Also, the possibility/probability of work (and limitations involved if taking benefits prior to full retirement age or even age 70) after early eligibility is yet another factor to consider.

For most folks who will not work on SS retirement, the payback period is somewhere between 78 and 82, IIRC, so if that is unlikely due to chronic health conditions, the earlier is likely the better. But a full analysis, rather than a snap decision is ALWAYS worth it for something so significant and relatively irrevocable is involved (which this certainly is).