SusanStokes

For example, one action duplicates the background copy, sets the layer to "screen" and adds a layer mask and allows you to lighten certain areas of the image to create an artistic effect (that I quite like).  

yes, they are adding extra pixel layers.

Yes, I am working in 8-bit.

Hello, I start with my standard 34 MB raw file, do my ACR edits, open in photoshop, run a few actions which creates multiple layers, and then my PSD file ends up being 511 MB.  Am I doing something wrong?  These are GIGANTIC.   If I flatten my image, they go down to 79 MB, which is still so big, and then I can't go back and make changes.

Thanks so much!