When I first heard about trekking poles, I thought they were for old people and/or wimps. But after doing 10+ mile mountain hikes both with and without them, I know that they can make your hike a lot more pleasant, especially on the way down.

If you don't often go on long hikes, you may want to rent instead of buying. You can rent these for a weekend from Sports Chalet (and probably other places) for less than $20.