I'm using Vim for a project that has a lot of pages per chapter, and Vim is a little bit slow. I want to create a local '.vimrc' file for this project with only the plugins I need, and I'm trying to understand when to use the "set exrc" option and local '.vimrc' files in Vim, and how to manage plugins with multiple 'vimrc' files. I understand that "set exrc" allows Vim to look for '.vimrc' files in the current directory and execute the commands in those files, and that local '.vimrc' files can be used to set project-specific settings in Vim.
My question is, when should I use "set exrc" in my standard 'vimrc' file, and when should I use a local '.vimrc' file in a specific directory? And how should I manage plugins with multiple 'vimrc' files, given that running the 'PlugUpdate' and 'PlugClean' commands in one 'vimrc' file may affect plugins listed in other 'vimrc' files?
Also, when I start Vim with a local '.vimrc' file, does it create a separate instance of Vim with its own set of plugins, settings, and configurations that are specific to the project or directory, or does it affect the standard 'vimrc' file and the plugins installed there?
I'm unsure when to use each of these options, and I would really appreciate a straight-forward answer to these questions, especially in the context of a large project with many pages per chapter.