actually i have never used vlan 1 and interface vlan 1 L3 interface.
Recently i noticed a spanning-tree loop in my network. Although it worked before with no no spanning-tree vlan 1 disabled, now it caused the loop.Vlan1 was enabled automatically on switches, might be the loop appeared
after disabling spanning-tree for vlan1.
I believe that any vlan should be included to spanning-tree if you have redundant links between switches, even for VLAN 1
Correct me, if i am wrong.