Retiring from a reasonably well-paying job is typically a 'one-way street', and so counts as one of life's major life decisions. Most people feel uncomfortable taking such a leap impulsively.
I agree.
For me, "the courage to pull the trigger" has been a lot more complicated than simply having the ability and desire to retire. At 56, I've been in OMY syndrome for the last 3-4 years. In fact, I could have retired more than 10 years ago with the same standard of living that I have today. The ability is there. The desire is there. But something is missing. What's missing is knowledge of the future.
If I retire today, my available retirement income before taxes (pension + WR + future SS) will be over 15 times what I need for my base expenses. If I work until 60, it will be 22 times. This sounds like a lot, and it is, but it's based on low base expenses.
More significantly, this doesn't include unexpected expenses that may - or may not - develop in the future. What about the long-term care needs of family members (e.g., mother, step-mother, near destitute brother)? Nursing home care could be $50K-100K/yr. What about pets/animals? I've spent $100K in veterinary bills for my own pets and the pets of friends during the last 10 years. What about the needs of friends? I almost loaned an ex-girlfriend $250K last year so she could buy out her brother's share of their parents house after her parents passed away. While that didn't materialize, she expressed relief that I was there to help if needed. What about me? Do I want to move into a McMansion, summit Mt. Everest, or take a sub-orbital space flight? These things aren't cheap.
It's often argued that time is greater than money. While there's a lot of truth to this, it's not absolute. Money can do a lot.
Currently, I'm paying the college expenses of a friend's 16-year old niece in the Philippines. She's a 1st year nursing student at a 4-year college. I also got her a laptop for school and paid her medical bills when she was hospitalized with dengue fever a few months ago. They want money upfront in the Philippines. No money. No hospital.
This young woman would not be able to go to college in an effort to improve her situation if I had retired 10 years ago without the extra resources to help. So while I might not be able to change the entire world, my decision not to retire back then means that I can change the world of this one person today. And to be clear, there is no altruistic motive here. I'm selfish. I'm doing this because it makes ME feel good.
I have more than enough resources to retire today, but I'll have even more resources if I retire tomorrow. Such resources could be put to good use. They may be needed for unexpected events. The future is not known.
Of course, this is and always will be true. Does it mean I should work until 90? Perhaps, but probably not. In fact, I'm currently going through one of those extra miserable periods at work that crop up every now and then. Unfortunately, more now than then. I may leave in the next month or two. But if I leave, there's no turning back. It's a one-way street. I'll be giving up something that may be needed for an uncertain future.
So for me, it's more complicated than simply having enough.