No, it is always faster to add in the beginning (except that add-to-list
has to scan the whole list anyway - as pointed out by @phils in a comment).
However, performance is never an issue with add-to-list
which is only used to customize user options like package-archives
and auto-mode-alist
.
The reason to add to the end of an alist is to avoid disturbing existing settings.
E.g., I had
(add-to-list 'auto-mode-alist '("\\.ts\\'" . js-mode) t)
so that *.ts
files would be edited in javascript mode, but I added it to the end so that as soon as Emacs came up with its own default mode, it would be used instead of js-mode
(actually, Emacs uses js-mode
for now but you got my point)...