You come to a point where ER is simply a leap of faith. You can do a lot of study, perform the calculations, devise a plan that has some reasonable comfort level for you - but then you still have to jump (or wait 'one more year').
But getting up in the morning is also a leap of faith. The alternatives to ER are a leap of faith (odds of getting in a car accident on that daily commute?).
Maybe I'm just rationalizing to make myself feel better (or less bad?), but when I think about the things that could derail a conservative ER plan, it strikes me that those things would likely derail me even if I worked another few years or so. Major medical bills? Ammo and MRE level of economic collapse? Zombie Apocalypse? Asteroid? Might as well enjoy the time I have left if any of those come to pass.
If we are talking the kinds of things that would wipe out a portfolio, working longer to have a larger portfolio might just mean you had more $ wiped out, and nothing left in either case. If someone sues you for 'all you are worth', that's still 'all'. Some risks you just have to accept.
And just because I love this quote:" Dogs and cats, living together! Mass hysteria!"
-ERD50