I carry either an E3 multitool like the Hero kit tool above or a Park MT-1 along with tire levers, tube, patches etc. and I've had to use the hex keys regularly for minor adjustments and the spoke wrench occasionally. So far I've avoided needing a chain breaker on the road. I also have a PDW 3rensho 15mm wrench from when I had a tandem with a bolt on rear wheel. I get enough use out a multitool to consider it worth the space.