Lengthen your poles before a descent and plant them actively ahead of you: that cuts peak knee load by 12–25% — the cheapest knee fix in the mountains.
Most people set their poles once in the morning and never touch them again. The whole benefit lives in adjusting them: shorter uphill, longer downhill. Plant the lengthened poles actively ahead of you on a descent and your arms take a share of the load that otherwise lands entirely in the knee — 12 to 25 percent less peak load, which you'll notice by day two of a multi-day trek at the latest. Two traps: first, don't brace far out to the side and don't use the poles as a braking anchor — they are extra balance points, not a handbrake. Second, they belong stowed on climbing steps and very narrow ridges, where you need both hands free; pick a model that folds away fast.