I'm asking this because the package
lineno has a thing that leaves a lot of commands in the .aux file (see here)... and I'm not sure if I should
\newcommand these to empty or if I should just load the package and forget about it.
I know the answer is very case dependent, as stated by David Carlisle:
it depends. If the package is
tikzthen it loads 100 files and takes half an hour doing stuff, if it is
indentfirstthen it doesn't. Conversely loading
tikzprobably doesn't have an effect other than taking time if no
tikzcommands are used, whereas loading
indentfirstin itself changes the document layout.
But I would like to know some other point of views, specially regarding best practices and if there is any approach that should be used for specific cases or with delicate packages.