Switching jobs is an exciting time, but it’s important you don’t forget about the 401(K) you’ve been paying into at your old job. Your 401(K) is your retirement nest egg. When managed correctly, it’s also one of the best ways to save - and potentially withdraw - money tax-free. You have a number of options regarding what you do with the 401(K) you were paying into at your old job. Each has its own pros and cons that may or may not be related to you depending on your individual circumstances.