I am a cyclist who rides road, trail, commutes, tours, and live pretty much car free so utilitarian cycling is also a big part of my life.
I carry nearly enough tools and spare parts to repair nearly anything and can almost tear my bike down and rebuild it on the road or trail... and this is not really a lot of stuff.
I always have my cel phone, a little money, and a first aid kit with me when I am riding.
I also carry water and food to sustain me on whatever kind of ride I might be doing.