One of the keys to good fiduciary practices is understanding that nothing can ever be put on autopilot. That especially applies to target date fund selection, since these funds are not fungible but will have different performance history, glide paths, risks and fees. Be especially wary of automatically signing on to your provider's target date funds without evaluating them first and without comparing them to available non-proprietary funds.
We all know these funds are complicated. We discussed these issues at our recent Adviser Roundtable with 401k provider Vestwell and afterwards Vestwell prepared this helpful summary of the issues to focus on in review. https://go.vestwell.com/404-and-QDIA-Takeaways The article also explains why your qualified default investment alternative (QDIA) notice also needs annual review.