I'm not a current Army PT, but I'm heading to Army-Baylor next year and I've spent a lot of time in Army PT clinics. I was also in the Army for 14 years so I can answer general questions about Army life.
1)Yes, you will change duty stations every 3-4 years on average (although sometimes less and sometimes more). You may have a little say in where you are stationed, but the needs of the Army come first. When it comes time for you to change stations you sometimes get a few choices to choose from.
2)You don't really have a say whether you get deployed or not. You are an Army Officer first and a PT second. If Uncle Army tells you you it's time to go. The operational tempo has slowed considerably over the past couple of years and deployments have started winding down. Most Army PTs do an assignment where they are attached to a Brigade Combat Team (BCT). A lot of PTs that I know that deployed did so during this assignment. If your BCT deploys you are most likely going with it.
3) RE: Pension-Yes and no. Right now you can collect a pension immediately after serving 20 years. The pension is equal to 50% of your base pay. That system is changing in 2018. You can still get an automatic pension, but I believe it is only 80% of the current amount. The military will also start matching contributions with the TSP (their version of a 401K). The amount that they match depends on how many years you have served. If you have some luck with the market you could come out ahead with this plan, but most people will do better with the old plan. Folks that have less than 12 years served when the new plan goes into effect in 2018 will have their choice of the two plans. There's a little more to it, but that's the Cliff notes version.
