Generally I use a pair of trekking poles. I prefer trekking poles to a single stick/staff for a few reasons. First, I like the hand straps that most trekking poles use, which mean you don't actually have to grip them at all, you can just let them swing on the straps. Second, I like being able to maintain three points of contact when crossing a river or on ice. Third, I appreciate the redundancy of having at least one pole if one were to break. Finally, I usually use my poles when I tarp camp as part of my setup.
During the winter, which lasts quite a while around here, I add larger snow-specific buckets to the trekking poles. Walking through deep snow and across ice seems safer with two poles.
I am sure I will make the change at some point over to a trekking pole but right now a stick is just fine for me. I keep a knee brace with me in case "righty" acts up while we are out but as long as it does not get worse (doctor words not mine) I should be okay for a few more years.
My trekking poles have saved my butt from falling a number of times and are probably saving my knees. I do a lot of rock scrambling and steep, rocky inclines and descents and they are invaluable. I have a lightweight, collapsible pair of Black Diamond poles that fits inside my day pack so I can put them away when I need my hands free. My heavy duty Leki poles are what I use for backpacking. There is a place strip backpack that I can stick my poles in and they collapse as well, just not as small as the Black Diamonds.
I use them for snowshoeing too. You can switch off the tip and the buckets. Very trick. Wouldn't hike without my poles.