Comment 2 for bug 591018

That gets extremely complex, Tim.

Autosave after every action could potentially slow down the UI. Unless the autosave after every action wrote a journal entry. (This has its own problems, but does not need to be a 100% perfect solution.)

Autosave after every X minutes is a good idea. That way a person can control the timing, or disable it.

Autosave on play would, as you point out, need to be an option that can also be disabled. Keeping in mind that it should be enabled by default.

A computer program must never, ever, ever lose (more than a minute or two) of a person's work.