High Quality Custom Neodymium Disc Magnets

It depends on what you are doing with it.  Most electronics are made with some magnetic shielding inside to protect against random magnetic fields.  However, if you have a MacBook Pro and grab a 2 inch N50 cube and slide it back a forth across it – I think there is a high probability it is toast.  Electronic devices such as speakers and microphones are especially sensitive as well as older style floppy discs and hard drives.  Generally the SSD style memory is not as affected by magnets but it would still be a good idea to not test it out just to answer the question.