hi,
most frequency separation tutorials teach using the healing brush, clone stamp, etc. directly on the high frequency layer. i usually don't like using these tools directly on a layer because it's destructive and sometimes i want to erase certain parts if i overdo it. usually when i'm using the healing brush i create and empty layer and set it to "current and below" and do my healing there. does this interfere with frequency separation?

I believe so. you can make a ton of different layers in the low section if you deem it necessary but it.won't work for the high as you'll be stamping the low section into the high will screw things up.

Hm. I suppose if it's that much of a concern to you then you could always make a
copy of the high frequency layer and then turn it off and keep it there in case you need to paint back in any of the original texture.

ok that makes sense. thank you for your help!

you can make a copy of the HF layer, clip it to the HF layer, and change
the blend mode to normal ( be sure to heal & clone with current layer only)

Create a snapshot in the History palette after you create the split layers and before doing any cloning then click the box next to it so you see a brush icon. Then you can use the history brush on the High layer to restore it to its original state.

just put the frequency seperation layers into a group and add a mask.