Are any of the unused fuse slots in the interior fuse box switched circuits? I have a dashcam hardwire kit that has a lead with a hardwired blade fuse intended for an ACC slot. I'd prefer to use an empty slot if possible so I don't have to cut that off and buy an add-a-circuit to tap into an occupied slot.

While I'm at it, does anyone know off hand which circuits are always on and which are switched?

Thanks in advance!

That may vary from year to year, but you can use a test lamp to find out which blank slots in your fusebox have Acc or Ignition power. Once you find one, the PG section (Power, Ground and Circuit Elements) of the FSM can tell you what bus is feeding it. Here's an example of the right section for an '11:
https://www.nicoclub.com/service-manual ... 1%2FPG.pdf

Thanks for that. Forgot to mention that I'm looking at a 2010 and took a look at the corresponding FSM. I was hoping it'd be a little more clear cut like the info here: https://fuse-box.info/infiniti/infiniti ... and-relays, but the problem with that is it doesn't say what the unused slots are for. I'm borrowing a multimeter to poke around but was hoping someone would know in the meantime.

You're better off with a $4 test light, quicker and easier and it's the only right way to test fuses anyway. To check a power circuit, use a device which draws power.