My trekking poles have saved my butt a few times when hiking slippery rocks and creek crossings with a 35-45lb pack on. Around East TN and west NC the rocks are coated with what I affectionately nicknamed 'teflon coated snail snot.' Engines who could get this stuff in their cylinders would never need oil. lol That said, going up steeper things where you might almost be hand over hand they can be useful and going down longer slopes (extend them a bit) and they just make it feel a bit more confident. Add in leaf season (late fall/winter) where unexpected mud and polished clay can have you start to slip and you'll find they are handy to have.
I wasn't sure at first so I tried a pair of Walmart ones ($19.99 for 2, twist-lock, nice height, still spring-loaded to take the shock off, etc) and frankly I liked them well enough save for the rubber grip meant very rapidly sweaty palms. Sweaty to the point it was streaming down my wrists.
A short while later I was in a local outfitter looking at the Leki's and ran across a very nice pair of MountainSmith Carbon's that are about half the weight, maybe less, work the same (but are a hair longer), and have a cork handle with a foam 'assist' lower that you an grab onto while climbing. I played with these and the Leki's around the store and I couldn't find the value difference between this $70 pair and the $150+ Leki's. A year and 30 hikes later they still look/work like they are brand new and now three friends have picked up the same pairs and are just as happy.
$20 is a cheap way to figure out if you like it and they will still support trekking pole tents. If you like them it's very hard to beat the Mountainsmith poles for $70-75 (or cheaper if you find them on sale).
The Walmart set is below and most stores seem to have them:
http://www.walmart.com/ip/Outdoor-Products-Apex-Trekking-Pole-Set-Black/36549842Wow! Just found my carbons for $58 which beats the $70 I paid hands down!
http://www.overstock.com/Sports-Toys/Mou...22/product.htmlHope this is a help.