Are you losing a decade of wealth? CA explains the math behind bad financial choices

Many people believe financial planning is complicated, filled with jargon and complicated investment strategies. But according to chartered accountant Nitin Kaushik, the truth may be far simpler and far more uncomfortable. He argues that most financial advice ultimately boils down to basic math that many people choose to ignore. In a detailed post on X, Kaushik explained how a few widely known financial rules can reveal whether someone is truly building wealth or quietly delaying their financial freedom by years.

Rule of 72

Kaushik began by pointing to the Rule of 72, describing it as one of the most honest ways to measure how time and money interact. The rule shows how long it takes for an investment to double based on the return rate. At a 10 per cent annual return, money doubles in about 7.2 years. But when funds sit in a savings account earning around 5 per cent, that same doubling takes more than 14 years. According to him, many people lose nearly a decade of potential wealth simply because they ignore the difference between these returns.

50/30/20 rule

He then highlighted the widely discussed 50/30/20 rule, which divides income into needs, wants, and savings. Kaushik noted that this is often the first financial guideline people break. When essential expenses like rent and groceries consume 70 per cent of income, it leaves little room for financial progress. In such situations, people are not building a life with financial flexibility but merely covering overhead costs. He stressed that allocating 20 per cent toward savings is not optional but the minimum price for long-term financial independence.

Housing

Housing, according to Kaushik, is another area where financial discipline often collapses. He referenced the one-third rule, which suggests that rent or home loan EMI should not exceed one-third of take-home pay. For someone earning ₹1,00,000 per month, this would mean housing costs should stay below ₹33,000. Yet many stretch their budgets to spend nearly half their income on housing simply to live in a more desirable neighbourhood. Kaushik suggested that this decision can quietly trade long-term financial security for short-term lifestyle upgrades.

20/4/10 car purchase rule

He also discussed the 20/4/10 rule for car purchases, emphasising that vehicles are depreciating liabilities rather than assets. The rule recommends putting down at least 20 per cent, limiting the loan term to four years, and ensuring monthly payments stay under 10 per cent of income. Extending loans to six or seven years to make monthly payments appear affordable, he warned, is a clear sign that the purchase may be beyond one’s financial capacity.

Investments in 40s

Another benchmark Kaushik mentioned relates to long-term wealth building. By the age of 40, individuals should ideally have investments equal to at least twice their annual income. Someone earning ₹20 lakh annually but having no investment portfolio at that age is already about a decade behind the curve. He explained that compounding requires a base amount to grow, and starting from zero later in life makes the numbers extremely difficult to overcome.

4% rule

The 4% rule determines if you can actually stop working. To withdraw ₹1 lakh a month safely, you need a ₹3 crore portfolio. If your current burn rate is higher than 4% of your total net worth, you aren’t retired you’re just spending down your principal until it hits zero.

Emergency funds

A 3–6 month emergency fund is not an investment; it is insurance. It keeps you from selling your stocks during a market dip or a job loss. Without it, one bad month can wipe out three years of disciplined investing. Financial stability isn’t about hitting every rule perfectly. It’s about realising that every time you break one, you are making a conscious choice to work longer than you originally planned.