Here is a new perspective. Say you contribute 7% to your 401(k) each paycheck. That means 7% of your working hours is dedicated to that contribution right? That is around:
33 minutes per day
2 hours and 45 minutes per week
12 hours per month
143 hours per year - almost 18 full working days
I think it is important to look at it this way. Some people just allow the 401(k) to default their investment selection for them - which, in honest, is not always a bad choice. Others may spend some time looking at the 30 pages of disclaimers, instructions, and paperwork and ultimately give up and select funds because they "look good". You spend an hour setting your allocation and spend 18 days over the next year contributing to it.
The cost of your mistakes can become massive over time. An expensive 401(k) investment selection can literally cost you tens of thousands of dollars in the future.
There are mistakes that can be avoided:
Look at the expense ratio of your fund options. If your 401(k) website or brochure does not list them, then go to www.morningstar.com and look it up using the ticker. The best predictor of fund success is the expense ratio.
Look into the number of holdings for any index fund options. While S&P 500 index funds offer exposure to around 500 stocks, many total equity market index funds can offer exposure to over 3,000 stocks.
Target date funds are not created equal. There can be good, cheaper options and there can be inefficient, expensive options. Do your research.
Your 401(k) is a component of your total portfolio. Tax-deferred and tax-exempt accounts can provide tax efficiency when considered as part of a household portfolio.
If you don't feel confident in your understanding of your 401(k) allocation, reach out to a financial advisor and get the initial work completed correctly.