Before turning 40, it is important to check if one has the basics of financial planning in place, such as emergency cash and life and health insurance. Saving at least 30-40% of take-home pay is crucial for those who want to retire at 50. It is also important to reduce unsecured loans to only have a home loan by the age of 40. Setting clear financial goals, considering inflation, and starting to save for retirement early are important steps.