Several say use the switched supply but do not say why they would do that. Interested if I'm missing something. The only advantage I see is you will not forget and leave the GPS on which would run down the bike battery after a day or so. I agree that is important but I have no problem turning it off when I put the bike to bed at the end of the day or end of a ride. Advantages exist for leaving the unit powered up for a complete ride even when stopping for gas or lunch.