i had an a-ha moment.
it has to do with my use of split jump-rings, and my up-until-now refusal to admit that they are inappropriate for connecting a clasp to a necklace.
my realization is this: i can ALWAYS use this kind of join between my necklaces and clasps. so much more reliable than open jump-rings! this technique probably has some official jewelry-making name, but i think of it as a twisted bead wire. sometimes it seems to take me an awfully long time to discover obvious solutions to problems.