A basic review of your liabilities (e.g. outstanding debts, mortgages) and some general estimates of future family expenses (e.g. college tuition, weddings) can give you a rough idea of how much life insurance coverage you should be holding.
However, getting a professional analysis of your financial situation and likely future expenses can provide a much higher level of security and assurance that you have properly prepared for your family’s future. Seeking the advice of a financial advisor is also a good way to ensure that your estate planning is handled properly, as the issues that arise are often complex and may require more coverage than you expect. There are many advisors that charge solely for a “needs analysis”, with others that may do the analysis for free but will be trying to sell you their products at the same time.
It’s up to you to decide which route you are most comfortable with, but with the magnitude of the investments you are making, seeking professional help may be advantageous. If you do seek the help of a financial advisor, look for a CFP (Certified Financial Planner) as obtaining the credential requires a minimum amount of experience and proven proficiency in the field.