The Human Life Value method offers a more grounded starting point: estimate your annual income, subtract what you spend on yourself alone (since your family wouldn't need to replace that portion), and multiply the remainder by the number of years until your likely retirement age. That gives a rough figure for how much your family would need to replace your financial contribution over time.
A simpler rule of thumb many advisors use: aim for cover of 10-15 times your annual income, adjusted upward if you have significant debt like a large home loan, or dependents with long time horizons like young children.
It's worth separating this decision clearly from investment products. A pure term insurance plan gives you the maximum cover for the lowest premium, because it has no savings component — it only pays out if you pass away during the term. Endowment plans and ULIPs bundle insurance with investment, but usually at a much lower effective cover for the same premium, since a chunk of your money goes toward the investment portion instead of pure protection. For most people, buying term insurance for protection and investing separately (through mutual funds, PPF, or NPS) for wealth-building tends to work out better on both fronts.