In 2010, the average US worker had been with his or her employer for 4.4 years, according to the Bureau of Labor Statistics. That’s a far cry from the 20-year tenure that’s been the American worker’s ideal since time immemorial, and it’s an indicator of an uncomfortable reality — jobs just don’t last like they used to.

While it may not always be possible to stay with the same employer for a few decades, it’s still possible to stay with one profession over the long haul. No matter how the job market changes, and no matter what new technology people become infatuated with, there are certain vocations that will never go away. These jobs serve ongoing, fundamental needs, and they’re immune to market forces.

Click ahead to see what some of these jobs are.

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