One thing to remember is that the interlink can cut the number of waypoints you can store in half, depending on the models you link. As an example, both my units can handle 3000 waypoints, as can the interlink. However, the way the sync works, you're limited to 1500, because the interlink needs to be able to store the waypoints from both units in order to run a sync. If you go over that number, the units really act freaky when you try to add a new waypoint. At least that's what happens to me the way I have them set up. Given the number of lakes I fish, I basically load the lakes I fish most often, then add and subtract as needed during the year.