A simple starting framework: estimate the annual income your family would need to replace, multiply by the number of years until major dependents are independent, then add outstanding large liabilities (home loan, education goals) and subtract existing savings and existing cover.
This produces an order-of-magnitude number for pure term life cover. Term insurance is risk transfer — it should not be mixed with investment products when the primary need is protection.
Review the amount when life changes: marriage, children, a new loan, or a large increase in income. Use the Insurance page on this site as a conversation starter, then bring real numbers to a discussion with a licensed adviser.