How to choose trekking poles outdoors?

Update:14 Jan 2020

First, let's clarify what is the benefit of trekking poles. This may make you more clear about your determination to buy a pair of trekking poles.
1. Trekking poles, just like ski poles, let your arms help you forward and up. Whether walking on flat ground or on steep hills, trekking poles can help you increase your average speed.
2. Trekking poles can reduce the impact of hiking on your legs, knees, ankles, and feet. Especially when going downhill. A 1999 study published in the Journal of Sports Medicine found that trekking poles can reduce the impact on knees by 25%.
3. Trekking poles can be used to deal with nuisances in remote areas. They can drive away spiny vines and sweep away spider webs on the road-which will make you feel more comfortable.
4. Walking with trekking poles can help you establish a steady rhythm, which can increase your speed. This is especially true on flat, non-technical terrain.
5. The extra two points of contact can significantly increase your grip on ground such as mud, snow, and gravel.
6. Trekking poles can help you maintain balance in difficult terrain, such as when crossing a river, on a small road with roots on trees, on slippery dirt roads. Keeping your body in balance helps you move faster and easier.
7. Trekking poles can be used to explore unknown places and give you more information. It is your third eye. You can use them to explore more about water, snow, and quicksand.
8. Trekking poles can help defend against attacks from dogs, bears and other wildlife. Put them on top of your head to make them look bigger or use them as weapons like spears.
9. Trekking poles can help reduce your burden. If you are carrying a heavy backpack, you can always rest on a trekking pole.
10. Besides trekking, trekking poles can also be used for other things. You can use it to replace the dedicated tent pole, saving a pound or two. Trekking poles are also much stronger and stiffer than tent poles, so they are less likely to break in high winds. This helps create safer shelters. It can also be used as a medical splint, and it can also be used to make ultra-light boat oars.