My wife and I have both been retired for almost 20 years. I am in my early 70s and she is in her mid-60s. Here is my perspective on early retirement.
First, if you have the means, do what we did. Fill out your bucket list and do as much as you can as soon as you can, don't wait for some vague day in the future. Ski those black diamonds in British Columbia, climb that mountain in Tibet, dive the Great Barrier Reef. Believe me, by age seventy, those black diamonds are going to be a lot more intimidating than they were at fifty. Face it and plan for it-- after twenty years, your body will no longer work as well as it did when you first retired. Being able to retire while everything still works, and works well, is a gift. Don't squander those early years.
Next, treat retirement like a job. Create an office at home if you don't already have one. Establish goals, rank them and continuously track them. Maintain a working calendar Build and stick to a budget. Take advantage of your spouse's skills (mine is a CPA).
Beware the volunteer trap. It's great to volunteer and it can make a huge difference in your community, plus you will feel a real sense of accomplishment from successful volunteer work. Just know when to pull back. In our case, every worthy non-profit we supported seemed to need the skills of a CPA and an IT specialist. Before we knew what had happened, we were back to working sixty hour weeks, but this time for free! Yikes! It can be very hard to say "no" when your skills can have a very real positive impact on other people's lives, but understand that you must establish a reasonable limit on what you can contribute.
If you don't already live there, find and move to the perfect place to settle. The area where we chose to settle houses the state's flagship university and our public schools (we still had school age children when we retired) are second to none . We have an outstanding medical center, housing is affordable and our air is the cleanest within the continental US. We have a symphony orchestra and two venues for live theatre. A national park is within an hour's drive and I can be skiing black diamonds--lots of them--after a two hour drive. And if I want to immerse myself in a culture where everyone around me is speaking French (important to me because that's what I spoke at home growing up), in a little over four hours I can be in Quebec City.
So if you do decide to retire early, treat it like the dream job you've always wanted and enjoy the ride.
Thanks for the sage advice. I am in my early 50s and thinking about the above intently. I own a company and will be working on it and it's success for at least the next 3- years. Covid gave us a chance to re-assess (in this world remote work) why we don't settle where we want to live now vs in the future. We decided to make the move to Hawai'i now, and to your point, make sure we are where we want to be. I'll be focused on working (a lot!) but have starting listing those ski resorts I want to hit up (not much locally). Thank you for the perspective!