Got some of this going on? Often times windows and doors have a piece of trim around them called brick molding. Often this molding rots out and creates a bit of an eyesore and a path for water to get in. Luckily it can be pretty easy to replace. It is sold at most home improvement stores or lumber yards. There are a couple of different materials it is made out of… vinyl, hardwood, engineered wood and pressed wood are a few. I would recommend staying away from the pressed wood variety which is usually the cheapest. This type of wood is not moisture resistant and is usually the first to deteriorate. Vinyl is very weather resistant but keep in mind vinyl expands and contracts quite a bit with temperature changes, it is also more prone to warping. As for replacing, usually the molding can be pried out and a new one cut the same size and reinstalled. Some times adhesive is applied to the back so it can be a little difficult to get out. Keeping a good coat of paint on this molding is the best method to keep it lasting a long time. If you are installing a new door or window and this molding is pre-installed make sure you paint it. The white coating that comes from the factory is usually only the primer for the paint which wont last long exposed.