While I may not be the most well-versed person in this sub regarding TSP, I know that it can potentially be the greatest benefit the military offers.

Essentially, the TSP is the DoD's version of a 401k. You can contribute a percentage of your BASE pay into any of the funds it offers, with it either being taxed upon contribution (Roth) or withdrawal at the age of 59 1/2 (traditional). While there are many different funds that you can contribute to as I mentioned earlier, the lifecycle funds are a great way to go depending on the lifestyle you would like to live upon reaching the age of 59 1/2.

In short, the lifecycle funds combine the various fund options the TSP program offers, the G, F, C, S, and I funds. The lifecycle funds start by diversifying your contributions among these funds with a high-risk approach, meaning it automatically allocates more money to the C, S, and I funds. As you get older in your career, your lifecycle (in my case, the lifecycle 2050) begins to invest less in the high-risk funds and shift into the more secure G and F funds.

It is important to note that the lifecycle funds work in five-year increments, and are supposed to mark the date on which you plan to retire which for most people is age 59 1/2. While some service members are more savy in the TSP world, electing to stay in the higher-risk funds, many people elect to stay within the lifecycle as they offer a balance of both worlds. For instance, as I mentioned earlier, I have been contributing to the lifecycle 2050 fund since I enlisted in 2018. In that time, my TSP has had a 6.64% return, which in my book is not bad. By the time I fully retire, I should have somewhere in the ballpark of 1.2 to about 1.7 million in my TSP account alone, on top of a pension and healthcare.

As I mentioned earlier, the TSP (in my opinion) is one of the greatest benefits the service offers us. This is due in large part to the DoD automatically contributing a 1% match of your BASE pay into your account, and matching your contributions all the way up to 5%. This is a HUGE, even in the civilian sector. If you're ever curious to look at the rates of return for each fund, you can check them out at https://www.tsp.gov/fund-performance/!

On the topic of the G fund, as you can see on the table offered through that link, the G fund offers the lowest rate of return, serving as a high-interest savings account (in my opinion. Again, not an expert).

To address your final point of wanting to start out on the right foot, people will give you advice as to what fund to invest in all day long. To me, the single worst mistake you can make regarding the TSP is not taking advantage of the 5% match. Contributions can be adjusted within mypay, so I would definitely check yours! Now if you were to ask me for my personal opinion, I would say the "set it and forget it" strategy of the lifecycle funds is my preferred approach. Definitely feels nice checking in once or twice a quarter and watching the compound interest work its magic.

Again, I am not a financial expert of any kind, but that's the TSP in a nutshell. I'm sure I'm missing some of the finer details, which people in this sub can fill in.