For me, I check the hubs before I leave. I had an experience once where I felt like going in there on a hub with only 1K on it, and when I got in there discovered some mud, as well as mostly grease keeping things running ok. The hube was protected by a rubber boot, and it engaged a groove that was bent out of shape, therefor no seal. So it pays to look before abig trip even without any real reason.

Anyway, once all that is in place, my main fear is spokes. With properly stress relieved wheels I have never broken one, but it coould happen therefore, I carry a carbon spoke, and some ground back regular spokes (and more recently am moving to Rohloff). So I don't really need an HP for the spoke thing.

So overall I don't carry this stuff, but if you need to, then I think the main reason for carrying a whip beyond a spoke change was to fix freewheels in you ran those. With cassetes that isn't an issue. I think that is why I have two whips in my tool box, one unopened. My current ride is a freewheel bike, but I have so many freewheels I don't think I will ever rebuild one.