I think one of the reasons that you're encouraged to volunteer, is because you're here for such a long time. All of this gives you positive things to brag about on Soldier of the Month, and promotion boards. For example, by the time I get to permanent party, I'll have 24 months TIS. I'll be an E-4. I should get a waiver for E-4 sometime this fall, and once I hit TIG for E-5, I'll be up in front of a promotion board, with not a lot of job experience. But if I have education credit (another thing you can do with your spare time, get an AA from Monterey Peninsula College) and volunteer hours, I look a lot better to the board, and for the chances of getting on the list for E-5. Volunteering also makes you look good to the cadre, and you often end up a leader, which is all positive, because odds are, you're going to run into this cadre later in your career, and they remember things. (For example, if I go to Ft Gordon, I may end up working under my former 1SG.)
Prior Service
For the most part, it's very similar to what the Iniitial Entry Training (IET) students do, except prior service are not restricted by the Phase Program. Class is 6 hours a day, PT three times a week, Battalion retreats once a month, etc. But since you're prior service, you may be tapped for extra duties. Which ones depends on your rank. If you're in a language full of officers, like Italian or French, you won't have anything extra to do in the classroom, and may well be the junior member. If you're in a larger language (Arabic and Korean spring to mind) you may end up being a section leader, or even a class leader. I know of IET E-4s who are section leaders, and it's not easy. Not only do you have to do the paperwork (attendance, etc.) but you have to maintain discipline, and be a role model, especially as prior service. You're not cut as much slack as the IETers.
Depending on your rank, there's a slew of other duties that are usually begging for people to do them. The 229th MI Bn is the largest training Bn in the Army, (Same with the 311th TRS for the Air Force.) and there's not enough cadre to do everything that needs an NCO to be in charge. If you're an E-5 or higher, you'll be voluntold to do things like grade PT tests, grade Common Skills Testing for the Phase Vs, be in charge of an entrance gate,(if they ever let the MPs go home) Staff-Duty NCO (E-6 and higher) Duty Driver and CQ, (E-5 and lower) helping run Field Training Exercises and Joint Language Training Exercises, which involves getting up at 0300 and not getting home until 2100 on a Saturday, and any other scut-work that they don't want to trust the IETs with.
Right now, housing is really flexible, but that's partially because of the MPs (have to house them somewhere) and partially because of the increase in students. Right now, pretty much any E-5 who can find an apartment is being authorized to move off-post. I heard a rumor that the same was true for E-4s in the Navy.
Additional Information for Sailors
(Note: This information provided by NAVYLINGUIST, a member of our Message Forum, who is a Language Instructor, currently assigned to DLI.
I am currently a Military Language Instructor at DLI, and a Chinese linguist (called CTIs or "I" Branchers in the Navy) for the Navy. I graduated the Basic Mandarin-Chinese course in 1995, and returned here as an instructor/Leading Petty Officer (LPO - a drill instructor of sorts) late last year.
First off, your language expectations. Although the Navy wants to give you something you have an interest in studying for a language, that there are also needs of the Navy to consider. The Navy does not put enlisted linguists through languages like German, French, or Japanese usually, so it is highly unlikely on an initial enlistment for this to happen. If you score above a 100 on the DLAB, expect to be put into one of the "tougher" languages like a CAT IV. Here are some languages choices you can expect, in no particular order: Chinese, Arabic, Persian-Farsi, Korean, Vietnamese, Tagalog, Spanish, Russian, Serbo-Croatian.
