Do other folks flatten their master files before saving them? That would seem to be sacrificing flexibility to save storage space which currently is relatively inexpensive.
One should always be careful that when asking for advice, you consider the advice you get carefully...what you are doing–saving the master file
with all layers as TIFF files (far better than PSD since TIFF files are publicly documented while PSD files are proprietary and TIFF files can contain everything a PSD file can except for Duotone) and if need be, PSB files is fine and it's what i do.
I often need to use PSB files because of panos using high rez captures (from IQ 180 files and Nikon D810). These files are way to large for saving as TIFF so I save as PSB with Ma as the last letters of the file name. The Xxxxxx-Ma.psb means Master file. For working files, I use the letters Xxxxxx-Wo.tif for the Working file. The Xxxxxx-Wo.tif is imported into LR.
When I need to edit the layered files which are PSB, I go to the Library panel and use the
Show File in finder option in the Context menu while the Xxxxxx-Wo.tif is selected that will take me to the folder where the tif file is located. Since I save the The Xxxxxx-Ma.psb in the same folder, the Master file with layers is right next to the Working file when the folder is sorted by file name.
Then I'll open the PSB file in Photoshop, do the work I need to do and save it as Xxxxxx-Ma.psb then do a Save As and add the Wo.tif to the file and save over the Xxxxxx-Wo.tif file in the folder. Back in Lightroom I'll make sure I select the image and use the command to Read metadata from file to update the LR version to have the newly edited file back in LR.
Since I use LR for printing and exporting for other uses, that dual file practice works ok. I do wish LR supported PSB files :~(
Oh, and I view TIFF files as the optimal file format to use (when possible) because it's documented and is therefore a better archival digital object file format than PSB...TIFF is not merely an output file format is like sRGB.