I have been looking at and buying used furniture for a number of years. I love the looks of traditional style furniture, especially in Mahogany. My favorite is Kindel and my Updyke desk. I also have Henkel Harris and Stickley. I was looking for a Councill desk. I like the looks of their open style desk with legs versus the drawers that go down to the floor. However, What I have noticed is the older the desk, the more the center sags. One seller called it the classic swag. I noticed this in the Councill dressers as well. I do not see this in my Stickley long dresser. Is this a design issue, material choice or was too much weight placed on top of the case goods? Can this be prevented or reversed?