I leave both a phantom powered and a non-phantom powered mic powered on but not won't use them. Is there any harm in this. One's a condenser the other dynamic.
'on but not wont use them.'
I just leave it plugged in to my interface because I use it as my sound card as well.
I don't think there's any harm in that. But to be honest, it's not a good idea to have equipment on all the time since they do heat up...I'm more worried about the interface...especially if it isn't connected to surge protection or power conditioners since a lightning strike could really ruin your day.