the_dunk_tank

Not intending this as a "uh, acktually" but just to add information on this front.

This is basically true across the board. If they, meaning your direct commander and their commander, feel the need to keep you around until your contract is up, then yeah, you're not going anywhere. Beyond your commanders there are others in basically like "HR" types whose job is to keep every job in the military manned at a certain leveled based on criteria that someone figures out. So if they need 10 people in your specific job and currently there are 10 or less, well, you ain't getting out even if your command does agree to let you be released early.

The only small exceptions to any of this are the obvious ones: you become disabled in some capacity to the point that you can no longer perform your duties and also can't be retrained into another less demanding position. Pretty rare, but it does happen to active duty sometimes. People use the term "med board" or medical board because a board of military doctors and others decide if you're fit to stay, etc.

But as far as voluntarily exiting early you can get out of an enlistment contract a few years early with commander approval (and beyond) to attend college and then officer training. I think this is more of a pause than an end though because you intend to reenter service as an officer in a couple years. This is also rare as fuck.

You can also get out early by being (or becoming) a conscientious objector. This is actually somewhat "dangerous" to do once you're active duty though since you are either saying you previously lied during enlistment (false enlistment carries some punishment possibly) or you have to prove that your mind has legitimately changed and you aren't cynically claiming the status simply to get out. Again, commanders hold nearly all the power here. They can rubber stamp it if, for example, some dude converts to Islam and marries a Muslim woman and they appear to now live/want to live a devout lifestyle. If he was previously not known to hold beliefs that prevent him from military duty, but has undergone a period of change and now outwardly holds different views, this is enough to get out. Assuming the commander(s) approve, of course.

You can also get out for failure to adapt type reasons eg inability to regularly maintain physical fitness standards. For the chair force this was just a simple honorable discharge (the normal default status). That may be different now for them and other branches. This still takes time to fulfill though since they'll force you to do extra PT, go to diet courses, might take over a year of failing to even get recommended to get kicked and you'll lose rank and put on shit jobs the whole way down as punishment.

You could also just straight up desert. They usually don't put much effort (now days) into finding people who do this HOWEVER it's like living life with a giant sword shaped warrant over your head and if you ever get picked up somehow you may be spending months in prison. Probably depends if you did anything else and all that stuff. Pretty sure desertion would make it impossible to be legally hired until it's resolved as well. Like it will pop up during initial onboarding at a new job. So you'll be working under the table forever or forced to leave the country.

So yeah, basically all of these are undesirable or extremely hard to pull off scenarios. Most people just end up doing the time. They basically got your ass.