[smm2000]

4% of 628k (safe withdrawal limit) is 25k - this is amount you can withdraw in pretty much perpetuity (for 62 year old). 25k combined with SSN (20k/year) is very close to average family income in US and guarantee good living in most cities in US (outside of Bay Area/NY and a few other zip codes).

Saving 10% is borderline enough to retire on if you do not make stupid financial moves (like moving out of market in 2007 or living in most expensive area in US). It's not enough to be financially secure - you need to save 20-25% for that (totally doable on software engineer salary).