I have 2 shift cables (Rolhoff) and 1 brake cable (MTB) slid into the stiffener of my jerry can (bikepacking bags). They pretty much live there all the time.
I've needed one once, not for my bike, but to help someone out.
I also keep the multitool, chain tool, extra quick links, spare brake pad set (discs), etc. etc. in there.

I haven't trimmed them to size, but I use heat shrink tubing on all my cable ends, once installed.