RACK BOLTS (solutions):

I don't like loctite. This is because, on my rear rack, long bolt (rack designed for discs, which I don't have) so more bending moment on bolt, it sheared off at the frame after 7 years. I was lucky, the threaded shaft was loose enough I could back it out with a dental tool. With loctite, that would have been impossible, even heating it up to soften the thread locker. The following info I thought up myself, I'm sure someone else has as well:

1) Use rack bolts that are long enough to stick out past the eyelet on the inside. Then if the head end breaks off clean, you can grab this to back out the shaft in whichever direction is easiest.
2) Make the amount the bolt sticks out on the inside, equal to a nut height (nylock nut if it will fit, or just conventional nut, you might need the latter or a thin nut on the drive side dropout), tighten the bolt, then put the nut on the back side and tighten. Bolt will not come loose. No need for loctite. If the bolt breaks at the head end (99.999% probability), you can back the nut off to expose the bolt to grab, unless the nut itself has enough grab to back out the bolt. Tighten the nut a bit less tight than the bolt head, you don't want to stretch the bolt and unload the thread engagement in the eyelet.
3) Rather than locktite on the threads, use anti-seize, so it doesn't freeze in place. Anti-seize is not as slippery as grease or oil, supposed to not change coefficent of friction versus clean, dry, and unrusted.
4) Put dot of bright nail polish on top (12 o'clock) position of bolt head, this will give you early warning if bolt starts to loosen. Do this also on crank bolts and bottom bracket cups.
5) Use good quality stainless steel bolts and nuts.
6) Carry spares in all lengths, they're small and light.
7) I did the same trick on the front derailleur cable bolt that was always coming loose, as cable position wants to unscrew the bolt. Haven't had to touch it since, 2 years.