cartridge demagnetization


Are there any telltale signs that your phono cartridge [especially MC] needs to be demagnetized, or is this just a preventative maintenance issue?
boofer
Thanks for all the input; Czbbcl: I did watch that video on UTube. Does anyone not agree that method is safe and effective?
In that YouTube video, it really isn't a demag, it's a deflux. Not the same thing, but I'm sure it won't harm anything and could be worth a try.

If it was a real demag, the MM cartridges he claims also benefit from this treatment, would be ruined.
Miyajima MC transformer has buid in demag. option.
I've seen Luxman Demags on ebay very often