From due.com:

A common mistake that many people make with their retirement investments is not starting early enough. Delaying the start of your retirement savings can result in having to make higher contributions in the future and missing out on the benefits of compounding interest. Another mistake is failing to diversify your retirement accounts, which can lead to potential shortcomings in your retirement funds. Additionally, being too conservative or too aggressive with your investments can negatively impact your retirement savings. Overlooking the impact of fees and costs, which can chip away at your overall returns, is also a common mistake that should be avoided.



Read more: 8 Common Long-term Investment Mistakes that Jeopardize Your Retirement