[jIM_Ohio]

First- your investment goal needs to be clear- retirement in this case.
Second you need to define a risk profile and translate that risk profile to investments. 80% equity-20% bonds is a good start. I would consider this moderately aggressive.
Third, you need to decide how much control of the 80-20 you want. Choosing targer 2045 is "cruise control". You will not need to do much after this.
Fourth- understand internal rates of return. 90% (maybe 95% or 99%??) of return comes from the underlying holdings inside the 2045 fund. The other 1-10% of return you get is based on buying low and selling high. There are two ways to do this... one is you will buy 401k funds with each paycheck. 26 times, 24 times a year type transactions. You have no control over the timing, but the timing of the purchases will influence short term return. The second influence of buying/selling would be transactions you or your fund manager make- 2045 fund will have a fund manager which sells 4% of large cap and buys 2% of small cap and 2% of bonds for example. Another example would be you choosing to sell 4% of fund A and buying 2% of fund B and 2% of fund C.

If choosing 2045 fund, the last criteria (buying and selling) will be removed from your control- as you would only have one fund to choose from (2045) and the manager is in control of this.

In your IRA, you may choose to open an account at Vangaurd, T Rowe or Fidelity (or somewhere else) and buy a large cap growth fund. Once you get around 5k-10k in this fund, you might choose to add an international fund, mid cap fund, value fund etc... If you maintain the 80-20 allocation in the IRA, you can buy and sell within these funds (sell the ones doing well, priced high, and buy the ones not doing so well- buying low). Assuming you chose good funds, this will increase your returns a percent here or there each year.

The more aggressive and volatile the funds, the more likely an 80-20 portfolio with frequent rebalancing will help your internal return.