I have used GCMH (the Garbage Collector Magic Hack) for many years. It’s great.

GCMH hooks itself in pre/post-command hooks. It (re)sets its idle timer on every command, which seems to be a good strategy, but also feels a bit too much.

Conversely, all gc-maybe-mode does is this:

• with a predefined idle timer (default is 5 seconds), call garbage-collect-maybe (from Emacs 28.1 or above) with a factor based on the current gc-cons-percentage, so it garbage collects if needed;
• add hooks to the minibuffer-setup-hook (raising the GC threshold), minibuffer-exit-hook (restoring the GC threshold), and the post-gc-hook (for optional stats in a buffer);

That’s it. It is pretty much the same GCMH hack, but as a cheap trick.

With custom advices, we can raise the threshold (gc-maybe-raise-threshold or gc-maybe-raise-threshold-briefly) for known costly functions; with a “restore” timer, we reset to defaults shortly after raising them (gc-maybe-restore-threshold).

I’m doing this in the very beginning of my init.el file (before bootstrapping straight.el), so adapt accordingly:

(load "~/.emacs.d/site-lisp/gc-maybe/gc-maybe.el" nil t)
(gc-maybe-raise-threshold)
(add-hook 'after-init-hook 'gc-maybe-restore-threshold 99)

Then, in my config file, with numbers that seems to better fit my machine:

(use-package gc-maybe
  :straight (:local-repo "~/.emacs.d/site-lisp/gc-maybe")
  :init
  (setopt gc-maybe-threshold-default (* 16 1024 1024)) ; 16 MiB
  (setopt gc-maybe-percentage-default 0.2)
  (gc-maybe-mode +1) ; set minibuffer hooks and idle timer
  :config
  ;; optionally log GCs in a buffer
  (setopt gc-maybe-log-stats t)
  ;; example function advice
  (advice-add 'save-buffers-kill-emacs :before #'gc-maybe-raise-threshold))

• GCMH: the Garbage Collector Magic Hack
  • [2019-03-11]: The original magic Emacs garbage collection hack
• EmacsConf - 2023 - talks - emacs-gc-stats: Does garbage collection actually slow down Emacs?
  • (Results) Please help collecting statistics to optimize Emacs GC defaults : emacs