My Roth IRA is 100% allocated into a Vanguard Target Date Retirement Fund with an expense ratio of 0.18%. 63.1% of this fund's holdings are in the Vanguard Total Stock Market ETF (VTI), which has an expense ratio of 0.05% and has outperformed the Target Date Retirement Fund over the last 10 years. What's more, their performance has been almost identical through both bear markets and the global economic crisis. Should I make the switch?