Index funds and ETFs are both popular choices for retirement investing because they are low-cost and diversified.

Index Funds:

• Bought at the end of the day
• Often easier for beginners
• Good for automatic investing

ETFs:

• Trade like stocks during the day
• Often have slightly lower fees
• More flexible

For long-term retirement investors, the difference is usually small.

The most important thing is choosing one and investing consistently.

If you are a beginner and want something simple, index funds may be easier.

If you want more control and flexibility, ETFs may be a better fit.

Either way, low-cost diversified investing beats trying to pick the perfect stock.