Another + 1 for the trekking poles. I'm mostly repeating what many have said, but...
I like to think I'm saving my knees a bit. I love them in the snow. They are great for extra balance a lot of the time. A little extra oompf on the steep climbs and big step-ups. Good as brakes on steep descents. I use Black Diamonds as many do. The Flick Lock is great. Way better than my first pair that were the twisty kind. Those really sucked in the cold. My gf claims they help her hike faster because she can get in a rhythm and involve her upper body. She hated them at first though. And they work well with my mini velcro tripod (summit shots, selfie type videos, etc).