Which speed should I use for mashing the potatoes with the potato masher?

How can I get the best results with the potato masher?

Can I process hot soups with the potato masher as well?

Is it normal that the force needed to fix the paddle to the masher bar gets less over time and/or that I no longer hear / feel a "click" when I assemble the paddle?

For what can I use my Philips hand blender whisk?

Can hard ingredients damage my Philips hand blender?