How to adjust what doesn't work

Hi Dan,
I find your advice on the polygons on the joints great! I can try to multiply them keeping two polygons straight in order to make them seem a single one. In this way they’ll start bending just when the leg bends…

Just a quick question. At the moment my model is rigged and the armor is linked to the mesh through automatic weights. Can I apply modifications to the mesh [i.e. adding a loopcut] or should I unlink everything, delete the weight paints etc.?
I’m trying to understand how back should I go in order to modify something.

For example if I discover that a bone is positioned unwell for what I understood all I have to do is moving in edit mode and move the bone I want to tweak. Once I go back to pose mode the bone remains where I placed and the weight paint still applies.

But what if I wish to slightly modify the mesh? Can I move vertexes or adding cuts without making a disaster? Is there any rule I can follow like the one really useful of the three loop cuts where there are the joints?

Thank you guys… you’re precious!