Janine advocates the 60/40 principle, for savings and investments. From her blog:
1. 60% you live on. This goes into your main checking account.
2. 10% goes into a long-term savings vehicle (IRA, 401k, Keogh account, solo 401k) for retirement. If you don't currently have a retirement account of any kind open two savings accounts at your bank. (One for long term and one for short term savings)
3. 10% goes into a short-term savings account (local bank or a money market account) for use in those occasional large-scale expenses (new tires) and emergencies (the water heater explodes).
4. 10% is tithed to a church or secular charity that is in line with your purpose. This is your ''rent'' for occupying space on the planet.
5. 10% is pure philanthropy. That's right, you just give it away for the benefit of the community at large. This primes the pump so that the Universe starts sending wealth your way.
But if you analyze it, it is really a 90/10 rule. 70% goes to expenses, 20% goes to charity, and you save 10%. While saving 10% of your income is a good thing, I think most people who are FIRE'd or on the track to FIRE in practice are saving a much higher percentage than that.
She says she used this method to become a millionaire in seven years. If that is the case, she and her husband must have had an amazing income.