Do postdocs ever end in your field, or can you build an entire forty-year career out of a succession of three-year postdoctoral appointments? If you can work a

Do postdocs ever end in your field, or can you build an entire forty-year career out of a succession of three-year postdoctoral appointments? If you can work as a postdoc forever, can you do this with confidence? Which is to say, what are the odds that you'll wind up washed up at age 34, or 44, or 54, driving the mid-21st-century equivalent of a taxicab, after your PI's grants dry up and you can't find any other PIs who need your possibly-quite-esoteric research skills? Tenure would help, of course. What's the ratio of assistant-professor openings to Ph.D.-level graduates in your field? Getting your own grants might help. In your field, do people who have done, say, five postdocs in a row routinely get awarded grants in their own names? (Full disclosure: I did a postdoc for fun, once. It was fun. There are many worse ways to spend three years of your life. But it was an expensive detour from my eventual career.)