I've been reading about companions from several different sources, but I'm still confused on one topic: Can I change my companions, and will I be able to change them back?

I have Boone and ED-E right now, my first two companions. Based on the fact there's a PS3 achievement that requires me to have all the companions, I assume I can get them all in one play-through. However, once I hire, say, Arcade, what happens to Boone? Does he go back to Novac? Can I go back to him at a later time and make him my companion again? Does the same go for all companions?

I just want to have it made explicitly clear that I will not loose my companion forever by acquiring a new one.

don't worry, when you tell them to go back home (or to the Lucky 38), they'll leave, allowing you to hire someone else, so when your done with that other ocmpanion, you can tell them to leave, and obtain your older friend. In short:

You won't lose any companion unless you done something terrible against their favorable faction, or were killed in combat on hardcoe mode or turned into an enemy.

You may, at any time, tell your current compainion to leave. If you have access to the Lucky 38 Presidential Suite, you can tell them to go there, or you can tell them to go home. Boone will go back to Novac if you say the latter.

You may only have one human companion at any time, so you need to get rid of Boone to get Arcade for instance.

You can get a companion back after telling them to go home. Just go to them and tell them you wish to travel together.

You can change an infinite number of times, unless you permenantly get rid of them, (For Boone, its joining the Legion, as he hates them).

Help this helps.

Yes, that helps a lot. Thanks for the info!