And if I die at 64?
The 401K is a transferable asset and SS is not. The breakeven age for waiting even a few years on SS depends on you living a long life. I'm in healthcare and realize that's not a given. I will be drawing the max rate whatever year I start, and honestly the difference isn't that great, I'll start drawing at 62 and it will start earning interest in another transferable asset.
Again, my strategy would be different if I was dependent on SS. My pensions won't run out like people only depending on savings. My strategy would also be fine tuned if I knew how long my wife and I will both live. I've seen far to many healthy people in their mid 50s not make it to their 60s.
I am not dependent on SS and have no idea if and when it will go away or how long I will live. I'll start drawing at 62 and put it in the bank for later, if there is a later. Regardless, we will do quite well in retirement whatever we do.