In reply to mypyrex:
I usually *take* 2 poles and an axe, because I revert to 2 poles once away from axe territory, especially in descent. I have a dodgy ankle and now, sometimes, in addition, a dodgy heel, so need all the support I can get.
Just back from the Alps and on the route we did Friday (Aiguille de Tour from Albert Premier refuge) used an axe only on the ascent to the bergschrund, but an axe plus one pole on the descent. The pole gave me that extra bit of balance/ control and took a bit of the load off my ankle. Then on the descent from the hut to Le Tour I used both poles.
When using an axe/ pole combo, I don't use the leashes on either (don't now usually use the leash on my walking axe anyway) so changing sides isn't an issue.
I've also practiced arresting when carrying both, because the instinct is to hang onto both if you fall, which seriously impacts the ability to do an axe arrest. I now have it down to second nature that if I do slip "properly" when carrying a combo, I'll drop the pole and conentrate on using the axe to arrest.