For many investors, the promise sounds simple: invest Rs 10,000 every month through a SIP for 30 years, earn an average return of 12%, and build a corpus of around Rs 3.5 crore. On paper, it looks like a retirement dream. But what if that seemingly massive amount is not as large as it appears? A Bengaluru-based chartered accountant recently explained why focusing only on the final number can be misleading and what investors should do instead.Bengaluru CA Meenal Goel shared a video on social media discussing a common investment assumption. Referring to the popular example of investing Rs 10,000 per month for 30 years through a Systematic Investment Plan, she noted that many people are attracted by the prospect of creating a corpus of around Rs 3.5 crore.However, she cautioned that the calculation often ignores a crucial factor: inflation. According to Goel, while Rs 3.5 crore may appear to be a substantial amount today, its real value could be significantly lower after adjusting for rising expenses over the next three decades.She explained that the corpus people consider large can suddenly look much smaller once inflation is taken into account. Rising costs of living, healthcare, education and daily expenses can reduce the purchasing power of money over time.You Might Also Like:Instead of SIP do thisDespite this warning, Goel made it clear that she is not against SIP investing. In fact, she encouraged investors to continue investing regularly, but with an important modification. Rather than sticking to the same contribution year after year, she recommended adopting a step-up SIP strategy. “Only SIP will not make you rich,” she said, adding that a step-up SIP can help create wealth more effectively. To illustrate her point, Goel shared a simple example. Suppose someone starts a new job and begins investing Rs 10,000 per month through a SIP. Instead of maintaining the same amount indefinitely, they should gradually increase their contribution as their income grows.She suggested increasing the SIP amount by around 5 to 6 percent the following year and then by 5 to 10 percent in subsequent years. Whenever an investor receives a bonus or a salary hike, a portion of that additional income can also be directed toward investments.You Might Also Like:According to Goel, this approach allows investments to grow alongside earnings, potentially leading to much larger wealth creation over the long term compared to a fixed SIP.Retirement planningShe also addressed retirement planning. Rather than treating a retirement corpus like a fixed deposit, she advised considering a Systematic Withdrawal Plan. Under this approach, retirees can withdraw a regular amount every month from their investment corpus, effectively creating a salary-like income stream while keeping the remaining money invested.