Retirement

I recently started listening to Caleb and noticed a lot of “You’re behind on retirement for your age.” What is the suggested amount one should have by age. I’ll be 23 this year and have a little over 8k in my employers TSP and about 1500 in a Roth IRA. Curious to see how much one should have every 5 years. So 25, 30, 35, 40, etc…