Most dishwashers require a space that is 24″ wide by 34″ tall. If you have changed your counter top or added flooring since the existing dishwasher was installed, check to be sure you still have 34″ of clearance from the bottom of the counter to the top of the floor. There are very few dishwasher models that are less that 34″ tall.
Most dishwashers require a 3/8″ water supply, 120-volt power supply, and drain connection.
In some cases the water supply valve will be an older size or corroded. In this situation the valve may need to be replaced to install a new dishwasher.
Dishwashers these days have a life span of about seven to ten years, and require some basic maintenance to work their best for that period of time. Factors like low water temperature, too much soap, the wrong kind of detergent, or a mineral build up in the tub may cause poor dishwasher performance.