It's not a straight forward question because the answer depends on the situation. A lot of the time you wouldn't be using the brush at all, but rather make a selection, and fill with black with Alt backspace. If I was using a brush in a layer mask, I would usually have pressure control size, but it might be better to control size with the Express wheel on the tablet, and click on the 'Always use pressure to control opacity' to the right of Opacity in the Options bar.
I thank you Trevor for your reply. I understand it's not a straight forward question, as it depends on what I am doing at the time.
In this case, lets say, I want to add a Level Adjustment Layer to increase the brightness in certain area of my photo and mask away other areas. Based what I mentioned:
Do you always put Pressure For Size on for and painting adjustments layers masks? And What type and size brush you should use for painting adjustment layers masks?
Same answer. Adjustment layers tend to need either very soft masking with a high level of feathering, or very precise using a small fairly hard brush.
But if I was doing the latter, it would be to adjust one particular part of the image, in which case I would usually make an acurate selection of that area before I opened the adjustment layer. This automatically fils the layer mask to your selection.
The sort of situation where I might be doing a lot of fine painting in a layer mask was where I had used Refine edge and output a new layer with layer mask. Refine edge often leaves errors that need touching up, but I would be using 100% opacity and changing the size, so I would have pressure change size.
It's entirely up to you to decided what works best in any situation, and to practice so you become familiar with the options - of which there are _many_.