Our axes have been through a season of use with one faint scratch on the spike end of the handle. One has been used for control whilst glissading, sort of self arrest without the urgency. Both have had a lot of use for support and stability. I have bunged up the bottom of the tube with half a plastic wine cork to stop the tube filling with snow and added a thin cord leash which I attach to my chest, just so the axe does not go sliding off down the mountain.
I decide each trip whether to take our 1 pound steel ice axes or the ultra light ones. I think the steel ones have had one days use. So for our use the Ti/CF ones are excellent.
I did read a report about a CF shaft breakage in Britain of a Helix shaft. The spike was plunged into snow when a slip occurred, as an act of self belay. It only went in about 9" before it hit rock. The shaft broke 6" above the spike. No injuries reported.
The user said he may have scratched the CF before the break by tapping the shaft against his crampons to dislodge balled up snow.