I normally pack on the heavier side of the debate about what contingencies to bring on a tour and what to trim to save weight. I even carry spare brake and shifter cables, which I think most do not.

The first tour I did with my Lynskey, that bike has replaceable dropouts held in with a pair of small M4 screws, the drive side one also is the derailleur hanger. And one of those screws started to come out, was damaged, I needed to replace it. Fortunately, my spare hanger in my spares bag had new screws.

Several years ago, after the second time when I gave someone a spare bolt because they lost a rack bolt, I now even carry a tiny bottle of thread locker (like Locktite) on bike tours. When I fly somewhere, I bring my S&S coupled bike, I even have to remove the racks to pack that. And I use a thread locker on my rack bolts, so carrying a bottle of thread locker with me is a logical thing to do, something most other bicyclists would never dream of. Some bike shops do not even have a bottle in the entire shop, so it is not that common, I think most bicyclists do not know what it is. Two years ago in a campground, another bicyclist had some troubles with his bike, I was chatting with him and when he said "What I really need right now is some Locktite." I started laughing because I had that tiny bottle in my toolbag. At 0.2 fluid oz, it is pretty tiny.