The document discusses how inflation impacts retirement planning and presents a mathematical model to determine the necessary capital accumulation and expenses to maintain a desired lifestyle after retirement given expected rates of return, income, inflation. It applies the model to an example scenario of an IITK professor planning for retirement in 15 years and finds their initial savings and expense estimates would be insufficient unless lifestyle is reduced by 20% during retirement. The model can be used annually to help individuals better plan expenses that account for inflation.