How long does the magnetism in a magnet last?
It will last till the end of time but the intensity of its magnetism will decrease continually in a specific proportion with respect to time. I am talking about Permanent Magnet. In an electro magnet the story is different. Its magnetic property lasts till current flows through its conductor coils.
In a permanent magnet permanent is the key word unless the magnet is violently jolted or moved through a strung magnetic field in the wrong way.
