in the dutch audio forum (where im active) the discussion started , if it makes sense to turn your woofer (for instance clockwise) because of material fatique. the weight of the woofer may have an impact on the coil.
so turning it every year may stabilise the quality on the woofer in the long run.
ive had some pretty old woofers and none of them had any coil problems.
no scraping sounds or anything like that.
you guys are facing the vintage stuff reguarly does it sound familiar. ther is some logic in it i think.
the discussion started when someone picked up some old Kef's and transported them on their side in staed of on the back and his coil was damaged. The speakers were old (22years). he didnt know for sure that the damage was already done before transport.