re: Ever resign from a job with nothing lined up?

Yes. I just took an early retirement package that'll pay me my salary through the rest of the year, plus insurance. I'm 68, but plan to work on putting in-place my own business consulting in several niche technology markets where I'm an expert for defense systems and low Earth space systems using certain unique technologies.

My employer did not expect me to leave and has already suggested they would want to lock up my consulting services. I don't think so. I know their limitations and can do much better waiting the full year for my NDA to expire.

So, technically, nothing is "lined up" but I have lots of options.