I'm studying at a trade school right now, to pursue a career not in the sciences. I'm also considering pursuing a degree(s) in a field of science later on, not just because of the additional job market, or the additional skills, but also because of a love and respect for the subjects, and a desire to contribute actively to them, in some small way. In talking with one of my classmates, though, I was a little discouraged; he is a chemist, with a Ph.D. and years of experience in the field. I can't remember the specifics or the reasons, but he had taken a few years off of actively working in the field, and he found that, if he ever wanted to return, he would have to go back to the post-doctorate level (not exactly the most financially secure stage in a scientist's professional life cycle). So basically, he left the field entirely so he could still support his family. Now, I know that this may look like a really bad idea for many reasons, but being that I'm still in the beginning stages of considering pursuing my love of science academically, I figure if there's ever a time to risk asking a stupid or obvious question, it's now. So. Hypothetically, if I were to pursue say, a Bachelor's and a Master's degree in a field of science, luck out and manage to find a good job in the field while working on another trade in my spare time, then leave the field for a few years to work professionally in the other field, would I still be likely to find a job in the sciences at all, or would that basically be a professional suicide? Is there a specific "danger zone" so to speak (a certain amount of time not actively involved in the field at which point you are considered worthless to an employer), and/or does this vary from field to field?