Your kitchen cabinets expand and contract with changes in humidity – this is a natural characteristic of wood. It is important to know that any pressure cracks at seams are a result of changes in humidity and are not a defect in the paint. In other words, if your cabinets did not have paint on them they would still expand and contract with changes in temperature and humidity. The paint slows down the effects from humidity but it will not entirely stop it. Keeping your home at a constant humidity throughout the year will limit how much expansion and contraction happens in your doors and drawers. The optimal humidity level is 35%.