BOSTON (AP) — Investors are increasingly cost conscious and providers of target-date mutual funds are responding. They're rolling out a greater number of low-cost options. These inexpensive funds come in two main varieties: those that rely on index funds and others with ETFs added in.

Target-date funds have "set-it-and-forget-it" appeal. Professional managers automatically adjust the fund's portfolio to a more conservative mix as the target retirement year approaches. That makes them appealing to investors who want to build their retirement savings without getting too involved in the process. What's more, target-date funds are often the default option for workers who don't specify how to invest contributions to their 401(k) plan.

But even hands-off investors should aim to minimize their expenses. A growing number of target-date funds aim to reduce ongoing expenses by investing in low-cost index mutual funds, exchange-traded funds or a mix of both. These funds are typically available to any investor with a few thousand dollars to start.