This decision is perhaps the most difficult. You'll likely have several options for screen size once you decide which Chartplotter features you need. Price is not the only thing that matters. Split-screen viewing on larger screens is easier and allows you to see finer details at a glance. You should consider the size of your screen based on how much detail you require or want to see. Also, consider your viewing distance. Anglers love to fish from boats with chart plotters or fish finders. A small screen attached to the bow of the boat can make it difficult for anglers to view from a standing position. A larger screen will allow you to view the screen clearly from far away or in a quick glance. I recommend that you get the largest screen possible to maximize your potential for growth.