At 21, I needed just about every dime I had to live on. If I had worked as hard as I could without affecting my grades, I could maybe have saved $2k.

In an index fund for 40 years with an average rate of return, after inflation, it would be worth about $35k.

Not enough money to make any difference at all, and to save any more would have probably had a negative rate of return because it would have negativity impacted my job prospects.

Now that I make more than enough money to save for an early retirement, I’m glad I had the experiences I did rather than save every penny I could through my 20s.

i.e., Convert your 401(k)'s to IRA, then convert the IRA to Roth via the "backdoor" that is not subject to the annual limits.