I don't carry very much stuff, I have never carried cables. It is an interesting though what set-up on a touring bike would make cables the easiest to McGyver, or replace on the road. I'm guessing stuff like internal routing might not be a plus.

I assume parts are in like new condition when I leave, so I tend to carry only stuff that life on the road tends to break. So inner-tubes are tops. I tend to also carry stuff I have broken in the past. I burst a tire casing, so now I carry an extra tire. I don't see any particular reason for cables to wear out, but if I had a bad experience I would probably carry them for ever after, unless there was some new tech I could employ that was supposed to eliminate the problem.

My overall approach is to build the bike with repairs in the field in mind, and to carry only tools that fit some specific part of my bike that I can repair on the road, and have parts for, if that is what a repair would require. I don't carry multitools, or stuff for repairs I can't make on the road. The exception being that I sometimes carry a fairly serious pedal wrench if shipping requires it.