The parts of break in that involve chemical processes are usually a one time deal: e.g. driving solvents out, the slow release of plasticisers, etc. (But not all chemical processes are unidirectional, there are reversible chemical processes whose direction may depend on heat or electric fields, etc. e.g. electrolytic capacitors.)
The parts of break in that involve mechanical elastic deformations usually relax back to near the unbroken in state given enough time: e.g. long chain molecules with dipole moments that align with the electric field (e.g. AudioQuest’s DBS stuff.)
The parts of break in that involve mechanical non elastic deformations (crystal boundaries, etc.) may be semi permanent, at least until things are moved around.
For cables it seems to me the most likely and most audible things are related to the dielectric and some rebreakin is often useful.