Its amazing to us here at Leading Edge Renovation for the disregard to install proper flashing.  This seems to be a challenge for builders and remodelers alike.  A simple piece of flashing, properly installed in the correct location, will solve a majority of water damage problems.  The confusing thing about this is the cost of this flashing is pennies compared to the other materials used to side a home.  Many of our repairs we are called out to look at are caused by the flashing.  Please make sure anybody you interview to work on your home has a knowledge base on how to use it and what to use.