If you are in Portland, go see the Jess Collins exhibition at Reed College's Cooley Art Gallery (until 7/20/08). From Cooley curator and Director, Stephanie Snyder, I learned that Jess began his adult career as a chemist. He abandoned the avocation, but funneled a methodical, scientific approach into his art process. He collected and filed images and materials for his art using a highly organized system. He mixed his own paints. He appears to have regularly invented and experimented with techniques. His prior career in science obviously informed his art.
The common career path for an artist starts early, and leads without interruption through a lifelong pursuit. If they wander or train for another career, they usually settle with art early in life, certainly before thirty. Many are forced into something else to get by at least for a while (Stella). Sometimes they work in advertising or a related field (Magritte, Warhol, Wayne Thiebaud). Some are perhaps writers or educators first, and artists second (Albers, Judd, Barnett Newman, Peter Plagens). Depending on the generation, some serve in the military (Diebenkorn, Kelly, Carl Andre, Robert Smithson, and on...), but leave as soon as possible.
Jess is an exception. Of course there must be others. Kandinsky taught law until age thirty. Gauguin was a stockbroker until age thirty-five. Tony Smith started sculpting at age forty-six. I'd like to make the self-serving case that career jumping improves art by bringing in original ideas from other disciplines. Jess is a prime example of someone who brought a fresh approach to art at least partly as a result of his training outside.