rerere (`git config --global rerere.enabled true`) is a useful configuration that allows you to record the merge resolution. Especially useful when rebasing a branch several times to follow upstream or when working with a long-lived feature branch that you wish to ensure applies cleanly. It makes following rebases / merges much quicker.

http://git-scm.com/2010/03/08/rerere.html

https://www.kernel.org/pub/software/scm/git/docs/git-rerere....