There are places you just would not want to hike without them--great for terrain. I have Black Diamond Trail Ergo's and they were about $100. Worth it. I take two but usually use only 1, at about long "cane" length. Works for me. The spare pole is strapped in tight with my sleeping pad at the bottom of my pack. Lots of other ways to strap and lash them on if you need to. Some pack have loops for them but I prefer them on the back out of the way. I do adjust on the fly as needed and that's why the flip locks are great. The rubber grip tips are for use on rocks/hard/concrete terrain and they were extra, like $5 or something. I got them but have not used them yet. In general you would use the spike tips for normal hiking in the woods, mountains, etc. I think if you were using the poles for Nordic walking you would use the rubber tips.