How much space do you have? Standard built-in dishwashers are 24 inches wide and sufficient for a family. Those who have less space or tend to use fewer dishes can opt for a compact, 18-inch built-in. For apartment dwellers or those with no space for a built-in, portables come in a variety of shapes and sizes, including countertop and rollaway.
Are you looking to reduce energy and water use? If so, you'll want to consider a model with a soil sensor, according to ConsumerReports.org. Sensors adjust cycles and water use according to the load's soil level, so you don't use more energy or water than necessary.
Do you use oversized dishes? Some models have tines that are closely spaced to accommodate more dishes, while others have far-apart tines to accommodate larger dishes; for this reason, appliance retailer Warners' Stellian recommends bringing a favorite plate or bowl with you, to use as a sizing guide, when you shop.
Do your load sizes vary? A two-drawer model will give you flexibility, according to HomeDepot.com; you can run one drawer alone for a small load or both simultaneously when your load is larger.
Do you intend to pre-rinse your dishes? There are many dishwashers on the market that clean well without any pre-rinsing -- but if you're the type who always pre-rinses, don't waste money on models with an expensive power-scrubbing mode.
Do you entertain often? Some dishwashers have special racks to handle a lot of glassware, and some have fold-down caddies that can lock in stemware.
Does it take you time to accumulate a full load? If so, you'll want to look for a machine with a rinse-and-hold cycle, which will reduce odors and prevent soils from setting, according to ConsumerReports.org.
Do you want a multi-tasking dishwasher? The latest models have some pretty exciting "next gen" features, notes CNET.com; for example, some hold an entire bottle of dishwashing detergent and dispense it as needed, freeing you from the task of adding detergent with every cycle.
Do you have particular dishwashing needs? Many of today's dishwashers have a variety of special cycles and options that may suit your specific demands; among these, are a time-delay option, which lets you set a later start time, and a quick-wash cycle, for times when you can't wait for a normal cycle to run.
Retailers like to sell extended warranties on dishwashers -- but ConsumerReports.org's warranty buying guide calls these "notoriously bad deals." That's because breakdowns often occur during the normal warranty period -- and if they occur later, repairs may cost no more than the extended warranty anyway.
If you still want one, ConsumerReports.org suggests checking your credit card agreement first, as some cards automatically extend coverage on purchases. You can also shop with retailers who offer extended warranties for no charge. Their final recommendation is to never pay more than 20 percent of the purchase price for extended coverage.