I was anti-pole for a long time. Then I did a couple of hikes with friends who use them, and I came around. But not all the way.
Where poles help
Descents with loose footing. Poles become a third and fourth leg, and that extra stability is real. My knees feel better after a 15-mile day with poles than without, every time.
Stream crossings. Poles turn a risky crossing into a confident one. Two points of ground contact at all times.
Heavy packs. When you're carrying more than 30 pounds, poles offload some weight from your joints onto your arms. On big miles, that adds up.
Snow and slushy mud. Traction. Balance. Period.
Where they get in the way
Scrambling. Hand-to-rock work. Anywhere you need both hands. Poles get stowed and forgotten until they snag on something.
Fast flat trail. Poles slow you down. The arm swing doesn't sync with a running or fast-walking cadence, and you waste energy.
Crowded trails. Be aware. Poles in public places are easy to hit someone with.
Which poles
Carbon are lighter, stiffer, and crack if you lean on them weird. Aluminum are heavier, bend instead of snapping, and are cheaper.
For most backpacking trips, aluminum is the better choice. I've bent poles and kept using them. I've never bent a carbon pole, but I've also seen carbon poles snap clean in a fall.
Folding Z-poles (Black Diamond Distance) are the best for running or stowing. Telescoping poles (Leki, Gossamer Gear) are easier to adjust for different users.
Grip
Cork feels warm. Foam is light. Rubber is cheap. I prefer cork for long trips and foam for short days. Rubber I'd skip.
