It depends on the material it is made of, but in general custom ear
protection lasts for years, and usually much longer than hearing aid
earmolds. (A hearing aid earmold is worn many more hours during a week.
Also there are acoustic issues that come into play with hearing aid molds
that aren't relevant to ear protection - Feedback, the need for an open
mold, the need for a very soft material, etc.)
But in general, the primary reason that any earmold needs replacing is a
shrinking and degradation of the material. This is probably caused at least
in part by the effect of the body's chemistry on the material. In kids, of
course, the other issue is growth of the canal. An adult's canal is pretty
stable in shape. There is some stretching of it over many years of earmold
use, but really the primary cause of change in fit is change in the
material, not the ear.
Tom Muller, MS, CCC-A
University of Arizona Hearing Clinic
michael_forrest wrote in message <01bd4dff$b5b85e40$dc3e63c3 at default>...
>Any ideas how often these have to be replaced (ie ear canal changes shape
>enough for the old mould to not fit any more)?
>>Context is individually moulded ear plug, as hearing protection, rather
>than hearing aid (but the same problem, I imagine, except possibly that
>hearing protection users might on average be a younger age group).