Inheritance - split from separate AO discussion

Whether there is a benefit in increasing a node's bit depth individually (as opposed to a chain of nodes) depends on the content and what the node does. For example a shape node might as well be L8 if it is outputting just black and white, but there is benefit in making a following BlurHQ node L16 or higher as that will make any gradations smoother. 
I tend to set a graph up to output metallic and roughness at L8, BaseColor C8 or C16 depending on content, Height minimum of L16. Normal C8 or C16 depending on content.

Whilst you would think it would be beneficial to work at 8k L32/C32 throughout, in fact that would be very inefficient in terms of calculation time and memory use within the graph and is likely to have little benefit come render time.

There are some good tips here:

https://helpx.adobe.com/substance-3d-designer/best-practices/performance-optimization-guidelines.html

Dave