I often end up riding at night. I need the extra batteries. I ride on/off road and about 1-1.5hr each way distance. I try to avid glass and such but I keep the patch kit more for insurance. I've found I do use the repair kit from time to time to retighten stuff all over the bike. The chaintool is the only thing I guess I could let go but seeing as I ride about 10-15 offroad and the fact that a chaintool is one of the hardest things to fashion out in the field I keep it with me. I used to carry front/rear lights, the light mounts, hand cleaners, hand creme, sunscreen etc in there but pretty much narrowed it down already to what I carry now a days with my knowledge of repairs (not great).

I may get a Topeak Alien tool which can slim things down a bit.

Edit:

10-15 = 10-15km combined round distance just on the offroad parts and not a total round distance of the trip.