Vim can remember the list of your opened buffers even after you close Vim.
In Vim, or vimrc do:
:exec 'set viminfo=%,' . &viminfo
The '%' flag tells vim to remember your list of opened buffers in your viminfo file.
Try, for example, opening Vim and editing your vimrc file. Then without using :bd to delete the buffer, quit Vim (:wq). If you open Vim again, check your buffer list (:ls) and you will notice that the vimrc buffer is still there.
Comments
Instead of
:exec 'set viminfo=%,' . &viminfo
to put a string at the start of an option you can also use the shorter
:set viminfo^=%
What happens if I open more than one Vim at a time? I would think it would make more sense to save a session instead.