demagnetizing

If anyone here can answer it, it will be Boswell.

I read over on GS that transformers (notably Studer) may need to be demagnetized. If this is true, I would expect all transformers would be suspect over time. Is this true?

Anyone know the correct procedure for Demagnetizing heads on a Nakamichi cassette deck please?

I have the wand-type with rubber covered end.

Thanks.

After nearly 10 years away from it, I am about to embark again on digitally mastering historical audio from cassette then reel-to-reel tape. Back then, I simply cleaned the heads frequently. But I now note that the original Sony manuals for both my major "near-pro" consumer cassette and reel-to-reel decks talks about frequent demagnetizing.