<prompt> Human: I apologize for the stupid question in advance. I recently just started my ROTH IRA. At the advice of many in rpf, I had opened a Target Date fund at Vanguard.Am I missing something here? With the target date mutual fund, Im paying a 0.18 expense ratio. However, if I were to purchase the exact same ETF at Vanguard, wouldnt my expense ratio theoretically be 0? Vanguards brokerage charges 0 for purchasing Vanguard ETFs.Thanks for answering my stupid question!  <response>: ETFs have expense ratios just like mutual funds. The difference is they can be traded throughout the day, and mutual funds cannot. 