A number of people I have spoken with recently have been retired sooner than they had planned. Many are not sure what to do with their 401(k) accounts, some like their investments within the plan and would like to keep them. Here are three points I think you should consider if you find yourself in this position:
I am not a fan of keeping money where you no longer are. Often, plans, and the investments within them change. If you are no longer employed where the plan was offered, you may find out about these changes when it is too late to act in your best interest.
Many 401(k) plan have higher internal investment fees vs. holding the same funds outside of that plan.
If you find you need to withdraw funds you will pay an automatic 20% Federal Income Tax when withdrawing from a 401(k). You may not be in a 20% tax bracket. When you withdraw from and IRA, you can pick your tax withholding.
If you find yourself in this situation, establish a Rollover IRA, then directly transfer the funds from the 401(k) to that account.