New Delhi, Sept. 5 -- Early retirement is not simply about quitting work at a particular age. Financially, it means reaching a point where your investments can support your lifestyle without depending on a regular salary.

That makes early retirement a more demanding goal than conventional retirement planning. Someone retiring at 45 could potentially need to fund four decades or more of expenses, while having fewer working years to build the required corpus.

"Age is the wrong unit. Financially, early retirement is the point at which your portfolio can fund your expenses for the rest of your life without you adding to it," said Sandeep Jethwani, co-founder, Dezerv.

The size of the corpus depends not just on income but also on how much of...