Stud finders are notoriously unreliable at finding studs; some will indicate a "rapidly shifting network of hundreds and hundreds of studs". Is there a way to determine before purchase that a particular stud finder will be more accurately named than most?
This answer to another question recommends using Zircon branded stud finders. Any other preferred brands or models?
Are there certain types of walls for which certain types of stud finders don't work?