Embarrassingly, I knew it since forever that git upstreams can | Not boring, and a bit of a condescending prick

Embarrassingly, I knew it since forever that git upstreams can be local dirs, but it always felt a tricky feature to use.

So, even when we all knew a git proxy would help speed up cloning the repos, I was somehow reluctant to look into this.

Well, git upstreams can be /home/dima/.my_git_cache/${repo_name}. In other words:
• Create a .my_git_cache local dir.
• Clone everything you need there.
• (You may even "clone" from your local, already cloned, dirs, just make sure to change their upstream to the true ones.)
• Write a cron script to do git fetch in all those .my_git_cache/* repos every few minutes.
• For your new repo, add this .my_git_cache as one of the upstreams, e.g. cache.
• (You may also want to mark it read-only by preventing pushes to it, just to be safe).
• Now, establish a habit of saying git fetch cache every time you need to sync with the "true" upstream.

Voila. Time saved: hours and hours. A rewarding git experience: priceless.