Does it matter whether I hold a target-date fund inside or outside my 401(k)?

Yes — target-date funds are best held inside a tax-advantaged account like a 401(k) or IRA, not a regular taxable brokerage. The reason is taxes: target-date funds rebalance and sell holdings internally, and they hold bonds that throw off ordinary-income interest, both of which can trigger taxable distributions you can't control. Inside a 401(k) or IRA, those events are sheltered, so the automatic rebalancing is pure upside. In a taxable account, that same activity can create surprise capital-gains and income distributions every year, making the fund less tax-efficient than holding separate stock and bond funds you control. If you want a hands-off single fund in a taxable account, an all-in-one ETF version is usually more tax-friendly. Use wealthserene.com/tools/tax-strategies to see where each holding belongs.