I am a 30 years old person who is planning on retirement at age 67. I expect to die with dignity at age 90 (I already have contract to do that) and leave nothing to anyone. My definition of retirement with dignity is to be able to support myself financially without support from anyone (family) or any entity (government/social security/pension).

I seeking your advice for retirement planning; how much should I save each month, how much should I have when I retire, and how much should I spend each month during retirements. I currently earn $72K/year and I can save as needed for my retirement. Assume an inflation rate of 3% per year and 7% MARR until age 67 and 3% after age 67.

Please make the necessary assumptions to answer the above questions explaining the time value of money.