It depends a lot on your age, and how much more modestly you’re willing to live, and whether you plan on leaving anything to anyone.

Having kids is a huge factor. Not only does it destroy 2 decades of potential savings, plus another potential decade’s worth it you put them through college for even 4 years - money which could supplement your retirement income; but also most parents want to leave something to their spawn, and are unwilling to burn down whatever capital investments to $0.

Childless couples (and the perpetually single) have many more options for early retirement.