None Should you qualify for a tax-deductible contribution up to the annual limit, you’re investing with pre-tax dollars up to the annual limit ($6,000 in 2019).
You don’t get a tax advantage today, but you do get to withdraw the money federally tax-free in retirement, provided certain requirements are met, including: the five-year aging requirement has been satisfied and one of the following conditions is met: age 59½, disability, qualified first-time home purchase, or death.
It’s important to remember each dollar you pay in fees is a dollar less that’s growing for future you, so you should compare costs of expense ratios and make sure you know exactly what you’re being charged.
For example, if you had $6,000 in employer contributions and $6,000 of your own contributions, and you left at the end of year three, you could take the full $6,000 you contributed + 40% of your employer contribution ($2,400).