The newer receivers (M, P, L) are less subject to wire damage than the old one, but we do still see breaks from time to time, or invisible damage that causes intermittency or static with manipulation (both from physical wear), or receivers that are just dead (moisture damage, likely).
Some users are a bit more subject to the wires being damaged. Points of failure tend to be: 1) very bendy ear canals that need a lot of pressure repetatively over time to get them all the way into the ear as well as more tension when the wires are pulled out, 2) insufficient space behind the ear such that the top of the wire is in a regular fight with the arm of the glasses, and 3) users who put the dome or custom tip into the ear canal first and then flip the hearing aid over the ear but sometimes end up giving the hearing aid a full 360 rotation to get there.