[yummyfajitas]

Also make sure to change jobs every few years so you can move money from the 401k to an IRA without a tax hit. 401k's tend to suck - high fees, low returns, little competition. Most of the funds in your 401k are there because a fund salesman took an HR person out to a steak dinner.

When you change jobs, always move the 401k into an IRA and put the money into low cost ETFs.

[cdjk]

Unless you have enough income to be over the Roth IRA contribution limits and want to make yearly backdoor Roth IRA contributions (non-deductible traditional contribution followed by a rollover to a Roth IRA). If you have a traditional IRA there can be some tax complications due to the pro-rata rule. If any traditional contributions are instead in a 401k the conversion is a lot simpler, and tax-free.

The other way around it is to open an individual 401k if you have any self-employment income, but that involves a bit more paperwork than an IRA.