The dryer may continue tumbling to prevent wrinkles until you remove the clothes. Most electric and gas clothes dryers provide moisture sensors, located at key contact points in the drum, to stop drying as soon as the moisture left in the clothes is low enough. The 1994 Federal Energy Standards resulted in dryers having at least one automatic-drying cycle. Sensors may also be thermostats that monitor drying indirectly by measuring the temperature of the air leaving the drum. Lint buildup slows drying, and lint that gets past the filter can be a fire hazard.
Some dryers have sensors to stop drying when clothes are damp dry for ironing.
An extra dry control allows extra drying time. A reversible door can make a dryer easier to use in some tight locations, especially if you may be moving. A light in the dryer is good if the dryer is to be used in a dark area. A program screen lets you see how far along the cycle has come. Differences between clothes dryers are largely capacity, price and dryer size.