I can only comment on my own experience. I used a single walking stick for years, but then got a pair on the advice of my daughter. Using the pair was an infinite improvement for me for balance, rhythm, and surer footing over rough spots. Your Mileage, of course, May Vary!

If you cross-country ski, try skiing with a single pole instead of two, and you'll see what I mean. Of course it's a bit early in the year to try that out yet!