Odds of Hanging On
As long as you like what you do (and live modestly), you can probably be an upholsterer as long as you want. This is especially the case if you work for more than one employer. Different employers will specialize in different areas, such as boat and auto upholstery, new furniture upholstery, and simply reupholstering worn or antique furniture.
The more you know how to do, the more valuable your services will be. Working in a couple of different shops helps your level of experience and know-how. You'll be able to command a bigger salary and, if you so desire, even start your own shop.