how long does a magnet remain magnetic when a load is present as opposed to when there is no load present?

if I rem correctly (its been a long time!)

it makes absoulely no difference at all to the magnet.

the "magnet protectors" you may have heard of are really only for Lab grade magnets of a known fixed flux density, used in equipment callibration. their main purpose it protect the magnet from phsical damage (impact etc..) and also provide a buffer for sharp changes in thermal gradients.

The way I interpreted your question is that if two magnets are forced to repel each other (or attract each other) how long will they repel/attract each other.

 

My answer is that it doesn't matter.

 

My Proof: I placed two magnets in a bottle a few months ago. I rigged it so the magnets would always repel each other and they would never flip over and attract one another. So far, they are still repelling. It is kinda cool too. You can actually defy gravity. If you push a magnet onto the bottom, outside, you can actually get the middle one to float in what appears to be mid-air. Will try to get some pictures up soon...