Really depends on your user habits. This is the question I always ask my clients so I can configure the wiring to meet their parameters. Some are straightforward with hot & ignition connections while depts like USFS has everything on a solenoid where EVERYTHING shuts off when the ignition is off. Typically, equipments that have "hot" and "ignition" are wired accordingly with the exception of the ignition which is connected to a delay timer, usually 1 hour. Switches are generally hot regardless of ignition position so you can run some lights while keeping the keys with you. To take it up a notch, you can either use a manual reset breaker or have a relay/solenoid to shut off power to the switches via a hidden switch, ignition switch, or a combination of both. If you just want to kill the power feed to the lights that's under 30a, a simple toggle switch will do.