The key to using stud finders is never trusting them and using multiple methods as a sanity check. For example, if it says a stud is as position x I'll sanity check by checking x-16" and x+16" because there should also be studs there. If nothing, maybe I'll try x-15, x-14, etc with the key being looking for some repeating pattern. Test moving vertically as well.
Combine with some knocking to feel/listen for a stud right against the wall vs an erroneously detected pipe 1/4" away.
I'll also use a neodymium magnet in certain situations to look for drywall nails/screws in conjunction with the other methods.
I don't fully trust any of these methods, but together they'll get you as confident as you can be short of having a couple hundred dollar detector or taking the wall apart.
Comments
The key to using stud finders is never trusting them and using multiple methods as a sanity check. For example, if it says a stud is as position x I'll sanity check by checking x-16" and x+16" because there should also be studs there. If nothing, maybe I'll try x-15, x-14, etc with the key being looking for some repeating pattern. Test moving vertically as well.
Combine with some knocking to feel/listen for a stud right against the wall vs an erroneously detected pipe 1/4" away.
I'll also use a neodymium magnet in certain situations to look for drywall nails/screws in conjunction with the other methods.
I don't fully trust any of these methods, but together they'll get you as confident as you can be short of having a couple hundred dollar detector or taking the wall apart.