Acrylic blanks are best in a moist environment, which is fine as long as your dentures are in your mouth; however, if they leave your mouth for a while, it is best to keep them in water.
Many patients take off their dentures at night, have their gums relax, and store them in water or a cleaning agent for a denture, such as Steradent. Acrylic does not respond well to impact forces, so great care should be taken not to drop dentures on hard surfaces such as tiles and pools, as this can lead to cracking of acrylic. Fortunately, these cracks are easily repaired, but this often means that you have to go without dentures for a day or so while they are being repaired in our laboratory. This may be a good reason to have a spare set just in case.