When building a fine piece of furniture such as a dresser or chest of drawers, the stock should be completely acclimated to the local climate before beginning the woodworking. In addition to other benefits, this will help keep the drawers from sticking due to expansion of the wood after the unit is completed.
In this case, we're not talking about the use of mechanical drawer slides, but when the drawer mechanism is nothing more than one piece of wood sliding on another. When the wood expands, the drawers can begin to bind, resulting in sticky drawers. This wood movement is a topic that we discuss fully in Allowing for Expansion and Shrinking.
The question is, if the unit is moved to a different, more humid climate and the wood begins to expand, what can be done to loosen the sticky drawers?
One of my favorite solutions is to use a candle, preferably one made from natural beeswax. Simply rub the candle's wax on the all of the locations of the drawers and carcase where the wood slides. You'll be amazed at how the drawers move much more freely.
Bonus tip: This idea also works well for doors in your house when they begin to stick or rub when opening and closing.