I'm really surprised at some of the responses....
to do this full time i'd recommend people consider having 6 months reserves of living expenses and another 2x of what your monthly gross is before you go fulltime.
So in that case someone with monthly expenses of 3000/month would ideally want roughly 18-20K of reserves before they even THINK about going fulltime. That takes care of the stress of not having to worry about the bills, food on the table etc so you can focus on your BUSINESS.
The next challenge is generating cashflow, and maintaining that influx of revenue. For that:
Assuming again you made 5K/month, 3K monthly expenses, and you lived a comfortable life. You would want your real estate business to generate an average monthly revenue of 1.5- 2x what you were making before, in this case 7500-10000. I say average to account for the flippers who get their pay day in chunks as opposed to month by month. The reason for 2x buffer in monthly revnue is simple, for the Buy&hold invester, a series of evictions, big ticket repairs etc can be detrimental if you only match you monthly salary, and likewise for the flipper, longer hold times, unexpected issues can cause your profit to fluctuate. So having at least 2 times, buys you peace of mind and detaches you somewhat from the volatility of the R.E investing arena. Some people might be able to cut it a bit closer, but like everything in life, you have to personally evaluate the risk and rewards of that decision.
Hope this helps someone :)
Happy investing!
Des.