"Whats the average life span of an infiltration unit."

"WOW, I can't believe noone's paying attention to the series, come one people, she kept it because if she doesn't then she doesn't get "born"!

If you remember, neither John nor Sarah sends her back, so someone else must've built her, (John's wife maybe?). Also, if you notice when they jumped ahead in the time-line, there was this scene where Cameron comes into the room, (after 3 days,) and tells Sarah and John that there is a group of people there with all they need already, like she already knew it but, at the same token didn't, because the "time lag" as John called it. Once they jumped the time line, (albeit they are still in it somewhere,) they changed things, well these things still have already had to have happened in Cameron's eyes, that's why there was "all of a sudden" some people "back from the future" waiting for them with their supplies. Therefore, if your keeping along that train of thought, if she didn't keep that one piece of Coltran, that she's made of, then she couldn't have been "born."

Gotta keep in mind that all this is taking place in Cameron's past still, so anything they do, can and does effect her. It's all still futuristic to Sarah and John, so they can't already know any of it. What all of them do becomes a matter of historical record to Cameron. Her look to me was one of concern that now she has more than John to contend with protecting, in that she also must now protect herself as well, so as to assure she can be "born".
"

"Sorry, but I have to disagree with this train of thought. Cameron already exists. She can't be "born", she's already there. As events in the current timeline change, the knowledge of these events are carried with the characters (John, Sarah, Cameron) so they know what happened and would be able to send "aid" back in time close to a point where they will need it. Hence the 4 guys sent back with ID's, money, and so forth.

What is not known, is what will happen now in the current timeline because they have changed it. Skynet also responds by sending back Terminators in response to the changes that take place in the past, to try and compensate for those changes.

Now, the point of Cameron keeping a bar of Coltan, (not coltran, people :) ) is largely unknown to us right now. She knows of events that have taken place and may still take place. She could be keeping for any number of reasons, all too many to speculate at this time. True, Fox says she is curious of her creation. Perhaps it will be used to experiment? Maybe it will be to build another Terminator for some purpose? It could be repairs, a weapon, a tool, a souvenier(sp?).. Who knows.
She also stated she was built at a factory at the bunker 37, which mind you, is still standing and has a functional Terminator inside. Granted he can't easily get out, if at all. The bunker is still there, and if the factory is outside the blast center, it will obviously be built after the bombs go off."

"Gotta keep in mind here folks, the John and Sarah of this time line are from the past, there's no way they can already know anything, Cameron is from the future, but there must be some kind of "time lag" before she knows what will happen in it. To Cameron, she's living what has already transpired but, if they change something it's going to take time before she "knows it"."