The graph below shows the path to $1,000,000 (assuming a 7.2% annual return) by the age of 60. The red line represents the coast retirement finish line you are racing towards. The sooner you get there, the less you have to contribute. With every decade that goes by the finish line gets twice as far from you, so you want to sprint to complete this race as quickly as possible.
If you invest $125,000 by age 30, you can COAST RETIRE! This means that even without further contributions, your portfolio can double to $250,000 by age 40; double again to $500,000 by age 50; and double again to $1,000,000 by age 60.
$1,000,000 with a withdrawal rate of 4% can cover $40,000 of annual expenses in retirement. Please remember that life may not work out as planed, so you might need to make adjustments to your path as needed based upon actual returns and your lifestyle. Hopefully this framework can excite you to take action today and start sprinting towards the path to a million.