My wife and I are both 75. She "retired" at 55 and I "retired" at 64. We are mortgage and debt  free and live very well on far less than 50% of our pre-retirement incomes.

My first question is why anyone would want to to retire earlier? Resting can be boring; being actively involved in almost anything social can be stimulating.  We continue to be active in our community, active mentally (cards) and active physically (bicycling and hiking). I continue to be involved in public policy issues - sometimes modestly paid and sometimes unpaid. The key is not the pay; it is keeping socially and mentally active by working on new ideas and new problems with new people.

Both of us elected to annuitize a large portion of our assets to have income security when we retired while keeping some investments for "splurge spending" (like annual foreign trips), 

Now, if only there was a way to avoid the aches and pains of aging.