You need to decide whether you want to use an ablative or a hard bottom paint. Part of this choice depends on local conditions, and if your boat stays in the water and how you use it. In this area, New Orleans, I use Pettit Trinidad, and it lasts a good three years. It does build up over time, and sooner or later after a several coats it will have to be stripped off. This is the biggest drawback to the hard bottom paints. You might check out Super Ship Bottom. It is made in Fla. and they told me their ablative would last three years in this area. I am seriously considering using it next haul out.