I think the primary reason for CA hinges breaking is using too much CA. People have a tendency to glue the hinge, then go back and glue it again just to make sure it is 'good'. That second/third covering of CA bridges over the hinge pivot area and makes the hinge brittle at that point. Continued flexing of that stiffer joint causes the hinge to break. I am only referring to the hinge breaking, if the hinge pulls out, that is a different problem.

The process I go thru is to assemble the pieces with the hinges in place, flex the control surface one way and wick thin CA into the slot on each side of each hinge. Turn the piece over and flex the surface the other way and repeat the wicking process. Let everything kick (do not hit with accelerator) and flex the surface back and forth a couple times. Do not, I repeat, do not apply more CA across the hinge line. After a mentor taught me this approach, I have not had a CA hinge break.

Woodie