Lots of great input already in this thread. Awesome! I was asked a question and a few comments were made that I would like to address 
1. My boys are 16 and sophomores in high school.
2. No mortgage. Paid the house off when I was 34 years old.
3. We never carry month to month debt on our credit cards. Paid off every month.
4. Vehicles were paid off until my wife was rear ended and her car was totaled. We have a 2017 sonata and a 2018 crv, both bought new and we pay less then $500 month total for the pair.
5. We max out both our 401k and our IRA, so we definitely do the slow and steady with our main retirement money.
6. Social security isn't something we are planning on as we plan to have enough of our own money saved to live on. SS will be like icing on the cake for us and we plan on taking it at 62 as soon as its available to us.
7. Our biggest concern is definitely the health insurance dilemma. As we all know, it ain't cheap to see a doctor in the U.S.!
8. We have read the F.I.R.E. book. It was a GREAT read and a real eye opener for us. Highly recommended.
9. I have thought about real estate/ rentals a bunch of times. But honestly, the upkeep just turns me off. Also it seems to be split down the middle between great tenants and a wonderful experience and horrible tenants and they never wanna own a rental again! My grandfather owned 70+ properties in the city where I live. Tenants were horrible and he was ALWAYS working. Not my cup of tea.
10. I think the early retirement thing for us is more about achieving the ability to say FU to our employers because we will no longer NEED a job, rather we will work if we want to and doing something that will be much more fulfilling and rewarding. I really wish to travel the country and explore at our own pace, not on the allotted vacation time from an employer.