What are the points, for every allegiance, when there is no going back?

As an example...can I run as an independent, do "Yes-Man" to the point of completing "Change in Management" and "You and What Army"...and THEN direct my upgraded securitron army to fight for the NCR by allying with them?

It would be good to know the point at which there is no turning back.

It should tell you that "you failed" the quests for the other factions and that means that you can't do any other ones than the one you chose.

Right before the second battle of Hoover Dam.

Edit: Oh oops, misunderstood OP. Gandler's right.

I have completed quests for both Yes Man and NCR to the point that I just need to talk to either side to start Hoover Dam battle and side with them.

How did you go that far with Yes Man without failing Don't Tread On The Bear? :huh:

What I'm looking for is a "stop here" type of info. Once I start failing quests it's obviously too late? I want to know how far I can go before I no longer have the ability to choose an alliance.
Keep in mind that I have not yet completed a full game so I really don't understand things like "before the second battle for Hoover Dam"...I wouldn't recognize that and have never seen it.

Thanks!

You will get the quest Beware the Wrath of Caesar and Don't Tread on the Bear when you are nearing it, you dont fail them until you go too far, but you get them before that, and a note containing a warning.

basically if you get the above quest mentioned you can't do any for the faction mentioned.

For me I got don't tread the bear and it said I needed to stop doing things for house, I did one more quest for house and lost NCR.

Yup, you get the quest as a warning, not as notification, you failing it is notification that you have lost access to that faction.

For House it is the quest where you check out the Omertas for him. I think it is "The House Always Wins IV" may be V. You can still do the Omerta quest, just don't report back to House.