I recommend the installation of a complete humidity control system in all my customer’s pianos.  As a field expert with the Dampp-Chaser Company, I have installed hundreds of these systems in my customer’s pianos.  It is important to note that when I install a new soundboard in a piano, I always put in a system to protect my work.  That demonstrates New England humidity variations are something I worry about.  Pianos I installed the system in 20 years ago now still look “like new”.