While both plans provide income during retirement, each plan is administered according to different rules. A 401K is a type of retirement account for employers. But as positive as all of this is, there are good reasons to have an IRA in addition to your 401 (k). An IRA not only gives you the ability to save even more, but it could also give you more investment options than you have in your employer-sponsored plan.
And if you have a Roth IRA, there's also a chance to earn tax-free income in the future.