I love hiking but am a little unstable knee-wise. I have a collapsible hiking pole that I am wondering if I should bring with me.

Is the footing loose or particularly steep on Haleakala trails?

The summit of Haleakala, where most people go to watch the sunrise does not require a hiking pole. If you are planning hiking into the volcano crater trails (something you don't do if just looking for sunrise) then I would bring it. If you are going to Kauai and doing hiking there I would definitely bring two poles!

John, thanks for the info, I should have specified that yes, I was intending on hiking into the crater.

Guess I'll be bring the pole!

Although the crater face slope from the summit is steep, the Red Sands Trail itself isn't...just some very long switchbacks. The trail is sandy because of all the previous hikers who have been on the trail. Imagine a shallow trench with a soft bottom and you'll get the picture. You are not allowed to venture off the trail due to the potential damage people can do to this delicate natural environment. So I'd be hesitant to recommend a hiking pole as it would be a little awkward to keep it close to you rather than to the side, but if it helps minimize the stress on your knees, go for it. Most people hike down to the first mini volcanic hole/crater (forgot what they're really called) they can reach, instead of all the way down to the floor, before hiking back up. It's definitely worth doing but if you're worried about your knees holding up, there is a pony ride available (only 1 outfit--ponyexpresstours.com) that may be a worthwhile excursion for you.

Hope this helps!

If you are a regular hiker, you will not need a pole on Haleakala unless you never hike without it.