People have laughed at me as I have seen this and really light planking many times on games. Both old and new. It depends on the environment of the game in its lifetime. I believe when stern installed it was correct. It warped after. If one has a high humidity house or really low humidity like we have in Colorado it happens. I have seen two months to two years. Storing in garage or storage space is the worst. No different than the sound board on a high end piano. Winter months are the worst. I did a high end steam humidifier trying to keep it constant all year long on my furnaces. Most humidifiers freeze if running with A/c. Many houses the humidity levels can be low single digits instead at times and in the summer the high humidity. 95 percent of time they warp low in the center. High in center usually low humidity newer in the games life. If you start putting a straight on games many will be discouraged. Just be careful on the Enviroment of the life of the game as it is a wood product. Wood burning stoves or fireplaces kill the humidity levels quickly. When you put kiln dryed wood floors in a new house the gold standard in dry climates is to put in new house and wait 6 months in that enviroment prior to install. Most skip the step as you can’t wait. I really try to only buy games from a dry climate anymore which I am. Even with a humidifier I am running it in the 34 per cent level but constant all year round. That is still low. A a/c unit removes humidity so in the summer I am flat also inside. Key is to avoid wide humidity movements. Warning don’t start measuring games or you will be disappointing.