Need to tackle all my crown mouldings & baseboards before I repaint. Caulk every crack or gap, no matter how small. Use latex caulk or a paintable latex/silicone blend. The key is to cut the caulk tube tip very carefully to create a tiny, 1/16-in.-diameter hole. Fill all the small cracks first. Then, if you have wider cracks to fill, recut the caulk tube tip to make a larger hole.