Replace 2 or all 4 tires at once?

[TGPilot]

So with a 1994 AWD Talon, or any other year AWD for that matter, do you have to replace all 4 tires at the same time? I ask this because I only need to replace 2 tires due to excessive camber wear on the passengers side. The other two tires are in pretty good to excellent shape.

My concern would be the difference in circumference of the tires and having different rotating speeds between front and rear axles.

Thanks, and that will be the last of my idiot questions for a little while!