I've had the same questions about the domane's durability also.

Every frame flexes to some degree obviously, and there is a possibility of frame failure even with conventional frames if subjected to too high of a load. But the domane flexes far more than a conventional frame and I think a reasonable person would ask how that affects the useful life of the frame.

I suppose one could simply assume that trek has tested the frame sufficiently prior to putting it on the market. But I would love to see some evidence of such testing myself.

The fact of the matter is, every frame has a finite useful life and I doubt the domane is any different in that regard. There are a lot of unanswered questions, and I suppose only time will tell.

I think some of us should email trek and ask them about their testing procedures for these frames. Who knows, they might even gift us with a response.