MohammadXX,
As-Salaam-Alaikum,
I plan to tap my account for 10% at first, then bump it up once (only one change allowed by TSP) later on, then eventually roll it over into a Roth to finish out. I am hoping (foolishly) to maintain a 10% annual rate of growth in retirement, thus avoiding drawing down the principle the first few years. I have a mandatory retirement age of 57, so by 65, there should be plenty left to live comfortably with lots available to help the kids, etc.
Just went to a retirement seminar, and they helped my put together this scenario...