Someone tell me how this TSP election works and when is it mandatory?

I hope I'm stabbing at the question correctly. TSP is essentially a 401 plan. When you turn 60, you can start pulling from it. You can either take a lump sum, pay the big tax bill, or pull it as an annuity over time. Another option is to roll it into something that will perform better in the commercial sector. TSP has about 35 mix/match options. Commercial has tens of thousands. So at 59 1/2, I rolled it out, and then the residuals when I retired. Use that as one of your money streams to meet your needs.

If you're talking about TSP contributions under the new MIL retirement, there will be a mandatory contribution that you can select from the 35 configurations. Most young folk will likely go for one of the longer term horizon plans which have more risk now and then tapers off later. There's a matching component where it's a no brainer to chip in for as that gives you 100 percent return every payday. Compared to civilian plans, it's pretty good. I recommend contributing 10 percent.

TSP mandatory? I was under the impression that TSP was an elective voluntary choice. After, I got out I rolled mine over to an IRA with USAA. Filled out a few forms and it was transferred. You can either roll it to a Roth IRA or a traditional IRA. I believe the max you can invest on the TSP is either 10k or 15k or you can invest a certain Percentage of your pay that will be deducted from your gross pay before taxes and you can choose a percentage to go to each fund of your choosing. All the info is at TSP website and if you have other questions I would recomend you talk to an investment or financial advisor.

Here is another familiar website's explanation of the program which is pretty good when compared to civilian sector plans. https://en.wikipedia.org/wiki/Thrift_Savings_Plan

"As of August 1, 2010, new employees will be enrolled in the TSP with a 3% deduction from their gross pay being deposited into the G Fund unless they make another choice.[2][3][4] Prior to this date, there was no automatic participation."