adding rocker switch

When adding a switch to control any electrical component, which side of the circuit would you place the switch. 12V Positive or Ground? Example adding any type of aux lighting. Would you place the switch on the positive side or ground side? Why? What are the pros and cons.DTS Performance

St Petersburg, FL

Usually the HOT side to isolate the load when off. But GND switching is occasionally used - especially when paralleling several loads or loads with different voltages (and common GND whether +ve or -ve). Sometimes GND switching is used for simpler or less hazardous wiring - eg, to GND switch a remote relay or load in a vehicle means only a single wire need be dragged into the cabin as opposed to f.ex +12V in to the switch and back out again. (That assumes the GND for the switch is taken locally.) Furthermore, if that cable shorts to GND (chassis/body) it won't blow a fuse etc tho it will turn the load on. But unless you have a special requirement as described above, generally the hot side.