When they improve their netops chops. Their recent junior-level mistakes (like improper spanning tree settings) are an indication of the level of their skill in this area.
The tree is built up automatically but you can weight the paths and also which is the start node of the tree. There are also a lot of settings that may or may not completely fuck you over or fix a problem.
Also you really want to disable STP on ports going to servers as this will 1) speed up recovery 2) prevent any malicious packets going out from them.