So for a long time I did my mozilla development using Mercurial (hg) and patch queues (mq). I've recently switched to using git instead. My mercurial workflow was a bit odd, but it had the advantage that I never lost my work and had to rewrite it. Never.

'git reflog' may be helpful. I've never lost work because of that command.

Git commits are immutable, git never actually forgets about a commit, so there's always a way to recover them (barring running the garbage collector).