Four legs good...Two legs bad
One real good reason to support Leki is the fact that they are one of the few companies who really understand long distance hiking and go out of their way to help thru-hikers. They are not that expensive considering the competition, you can get great poles for about $80 per pair and they have a two year warranty, most other companies have a 1 year.
As far as damaging the trail...they don't do much. Are we to stop using tent stakes cause they make holes in the ground? I think shelters are more of an eyesore than tiny holes in the trail. I would say the only drawback is the damn noise, but not enough for me to stop using them. Also good for fording rivers, smacking wild dogs, playing wiffle ball in camp, setting up tarps, leaning on and they keep your hands in a more natural position.
Another view on trekking poles
Ray Jardine dismisses poles "In actual fact the poles add to the toal stress, because of the weight. Lets say, that each pole weights 16 ounces. Two pounds lifted from the ground between each of 2,000 steps equals two tons of unfavorable stress that the poles add - per mile to your body".
So all you ultra lite hikers if you believe in Ray and use his advise you should not bring poles. Maybe some of the engineer types can comment on the math; what is missing in the statement is the benefits of hikking poles to take stress off the knee's.
Got the quote from Backpacker light web side on a article entitled Beyond Backpacking: Under the Microscope.
The article takes a look at some of Ray's practices and makes a few comments on Ray's practices.
I for one think think Ray has done a lot for light weight hikking by getting us to think for lighter weight gear and try and move away from the 8 pound packs. I think his advise to use tarps and bring mininal clothing is genrally sound. I myself am a firm believer in poles.
Pete