2 schools of thought, bring everything to fix anything, or bring nothing and hope for the best. Tbh I dont expect my bike to break down in the next 200 miles, whether its continuous or short trips. But I still usually carry a lock and a phone, and basic tool set to adjust or clean carb, swap plugs, and maybe even replace a cable. I've definitely buffed sachs clutches on a sidewalk with little more than a leatherman, a screwdriver and a cheapo double ended spark plug socket.
How much do you trust yourself and or your bike and at what point is it over? Lock it up and call a cab oclock.
I've done a lotta 100-250 miles trips sometimes in a day, and never broken down, but I've also had to lock up and walk miles to show up late for work.