My experience with target-date funds after 8 years of holding one in my 401k.

Target-date funds are designed to automatically shift from a stock-heavy to a bond-heavy allocation as you approach your retirement year. They're the lowest-friction option for people who want to invest without thinking about asset allocation.

The pros: truly set-it-and-forget-it, professionally managed glide path, total diversification in one fund.

The cons: expense ratios are higher than building your own three-fund portfolio. My target-date fund charges 0.12% vs roughly 0.03% for a DIY VTI/VXUS/BND portfolio. On a $300,000 balance, that's $270/year in additional fees — not catastrophic but not nothing.

More importantly: the glide path may not match your actual risk tolerance or retirement timeline. A 2045 fund at 45 might be more conservative than you'd choose for yourself if you don't actually plan to retire in 2045.

For 401k plans with limited fund options, a target-date fund is often the best available choice. For people who want more control, DIY is worth the minor additional complexity.