What happens when you are in the MentalStateCalledFlow. The most work gets done in this state, and when you get yanked out of it by a crash, is when you realize you haven't saved for two hours, because you were in the MentalStateCalledFlow. You are then in for a case of ExtremeFrustration.
Auto-save seems like the obvious response but when your auto-save fails you,as can happen on some apps, you won't know it until it's too late. A solution is to set up a secondary safety net. Set up a 10, 15, 20 minute reminder popup that forces you to save.
See OneButtonTesting, and change your editor or change your editor