Hmmm it all depends on what your lifestyle is like... I was listening to a guy on the radio that retired at the age of 35. He had $450,000 in savings and on average brought in a 8% return on his money. So basically he was bringing in $36,000 a year in interest... He did have to pay taxes on that too but he really didn't have many expenses and his house was paid off. The reason he was on the radio show was to announce his new book on how to retire early hehe ;)
I don't think I will ever retire, I'm paid to do something I really enjoy
DH