What do I do for a pair of orthotics which, after 4 years, are now squeaking and spoiling all attempts to sneak around. I've put them in different shoes to no avail. They are custom-made plastic ones and have been well-behaved until now.
mary75--I have big orthotics (KAFOs) and the latest new shoes were the culprit. Squeaks and groans for a couple weeks until the shoes were broken in to them. Try some cornstarch in the shoes as a buffer. KAFOs are Knee-Ankle-Foot Orthotics. They extend from the upper thigh to the bottom of the foot. Yours are FOs.
Do they squeak from the soles, as they touch the floor? If so, you could try roughing up the soles with coarse sandpaper so they are not smooth -- that would help.
However, if the are squeaking from the upper part because of the flexing.... I think you're (they're) toast. Normal shoes made of leather or synthetic materials often flex enough that finally the squeaking stops. Something made of an indestructible thousand-year substance like Crocs -- not so sure that will ever happen.