Integrating Local Additions provides a nice explanation of how to manipulate
TEXINPUTS or register a local texmf tree.
Q: When integrating local additions, is there a reason to prefer one approach over the other?
I'm guessing that
TEXINPUTS is just regarded as the quick and dirty approach while registering a local texmf tree may be a better idea if you have a lot of files within a logical directory structure to which
latex needs to be pointed.
If I'm missing something here I'd love to hear about it :)
This question is a follow-up to my post Texmf tree with MikTeX