I have a 590. At first I powered with switched power and did not like the unit shutting down every time I stopped for gas or anytime the key was turned off. That goofs up your route you are following requiring a restart. Additionally my 590 and I would think all are limited as to how many routes it will track. When it shuts down and you power back up it starts a new route so if limited to 20 you might have several tracks in one day and reach the max sooner as well as hard to save the route if following someone and you want to get a copy. The down side is you have to remember to turn it off at the end of the day. It is very noticeable when it is on and will not run the battery down even overnight. So noticeable when stored in a garage and if stored outside I would think the unit is coming off the bike anyway. So I changed mine to full time power and have only run the battery down once in several years.