New Delhi, Sept. 28 -- How much was Rs.5,000 worth five years ago? Not in investment terms, just in everyday life.

For someone who began a monthly SIP with Rs.5,000 and has continued with exactly the same amount ever since, that question is worth considering. The original investment may have been sensible for the salary, expenses and financial goals at the time. Five years later, those numbers may bear little resemblance to the old ones.

Yet SIPs are easy to leave untouched. That is part of their appeal. Once the instruction is in place, investing can continue without a fresh decision every month.

Convenience, though, does not mean an investment should disappear from view.

A SIP mutual fund investment puts a specified amount into a mu...