Electronic stud finders changed all that. For an accurate and quick stud finder we recommend the franklin sensors 710 precision stud finder.

Best Stud Finders 2019 Stud Finder Reviews
What does deep scan mean on stud finder. 38 mm red leds light up every time a stud edge is approached. Deep sensing technology the profinder 5000 has more sensor pad area so that you get a deeper scan one step operation just press button. Power button power button. The multiscanner440 features four scan modes to detect studs metal and live unshielded ac wiring up to 1½ in. In a way these stud finders are like a touch switch on a touch sensitive lamp. Theres no need to switch to a higher powered scanning mode or make any changes to the device in order to make use of the scanners since they are always active and always ready to give you a strong reading.
It can detect more than one stud at once and the deep scan mode allows you to detect studs in thicker walls. The tavool stud finder features a multi scanner that can be used to quickly locate both metal and wood studs pipes and live wiring. Deepscan mode doubles the scanning depth to 1 12 in. The spotlitepointing system automatically displays a beam of light over the edge of a stud or near metalac. Multiscanner models with metal scan mode can be used to verify whether the stud located in stud scan or deepscan mode is metal. Patented spotlite pointing system audio alert and a green led signals when the stud edge is reached.
Includes a deep scan mode that can detect objects through two layers of drywall up to 1 12 38 mm. Stud scan mode locates the edges of wood or metal studs up to 34 in. Large lcd screen utilizes a target indication bar to clearly locate objects behind a wall or ceiling. When placed on the wall the profinder 5000s led lights instantly indicate the location of studs 13 sensors the profinder 5000 has 13 individule sensors compared to 1 in conventional sensors. The real benefit of this stud finder is its amazing deep scanning sensors which are designed to penetrate thick walls more easily. The shallower stud scan mode picked up the pipes too just not consistently.
In studscan and deepscan modes the tool will indicate the presence of wood or metal studs with a stud indication but will not indicate whether the stud is wood or metal. Deep scan mode identified objects inside the test wall yet the studsensor wont differentiate between materials. They are using changes in capacitance to sense where the stud is. They give you an amazingly accurate view into the wall and show you exactly where each stud is. 38 mm deep behind walls floors and ceilings.