How much retirement income i needed?

Recently, one of my friend asked me how much do i need for my retirement? I quickly answered him USD900 (RM3000)per month when i retired by the age of 55 then he just show me the calculation and shocked me that i need approximately USD280,000 (RM900,000)and it is based on the following assumptions;

Current age = 40
Return on investment = 6%
Inflation rate = 3%
Retirement age = 55
Number of years requiring retirement income = 20 years

When i think about it then i have few choices when i am retiring;

a. Reduce my living lifestyle (migrate to the rural area)
b. Save the money
c. Depend on my children
d. Delay my retirement age

Question across my mind, which choice is more realistic? What are my biggest retirement concerns?

It is a very broad question to ask simply because everyone of us have a different life goals, right? Some may just need monthly income of USD300 (RM1000), some may say nobody can predict what will happen tomorrow, cannot think too much and etc. I am worry that if i am ever to live longer and when can i retire?

I first heard the word 'financial freedom' way back in 1998 from one of my friend and it really inspired me simply because he dare to dream as he told me that he want to be financial freedom by the age of 40.

to be continued....