I think there is a recent IRS ruling that effectively makes these conversions tax free, so the timing and frequency are not that important any more because there are no adverse tax consequences. Under my plan, I have a 2 year "seasoning" requirement so I have to wait for 2 years from the time the funds are contributed before I can do an in-service rollover or conversion. That automatically implied some tax consequences. But based on the IRS ruling, you can rollover the amount originally contributed after tax to Roth and any earnings on that amount to a traditional IRA, so that is what I did earlier this year. I think some people refer to it as a split rollover. In any event, I did my first split rollover earlier this year and the process was pretty easy. Our 401k admin is Fidelity and I have accounts at Fidelity so they basically did an internal transfer among the accounts. No form to sign, I did it entirely over the phone and then just got a confirm in the mail. I am planning to do these once a year from now on.