Actually, it's pretty common practice. If you are doing research in a given area, and publish a lot, you wind up having to describe the experimental setup a bunch of times, so you just cut and paste from the previous paper. Particularly for conference papers, where you may be choosing conferences where there isn't much common attendance, you'd present essentially the same paper, perhaps with newer data each time.
For journal pubs, the editors tend to want unique and new stuff each time, to the extent of asking you to sign a statement or accede to a policy that says you haven't published the stuff before.
Created on Monday, February 12, 2001 3:38 PM EDT by James Lux