A common starting approach: estimate your monthly expenses in today’s terms, inflate them forward to your retirement date, then estimate how large a corpus is needed to sustain that spending for a retirement that could last 25-30 years.
Two variables matter enormously: the number of years until you retire (more time means more room for equity and compounding to do the work) and inflation, which quietly erodes purchasing power more than most people budget for.
This is genuinely a case where a rough number today, revisited every few years as income, goals and family circumstances change, beats either ignoring the question or trying to nail an exact figure decades in advance. The Goal Finder tool on this site is a starting point for that rough number — treat it as a conversation opener, not a final answer.