Pre-rinsing not only takes time and wastes water, but it also prevents you from fully utilizing your appliance's performance. And for good reason: by rinsing dishes, you assume there will be no more stains.
However, dishwashers operate at high temperatures to ensure that dishes are perfectly clean at the end of the wash cycle.
Hot water with detergent cleans dishes, not pre-rinsing.
If you get into this habit, you're limiting your dishwasher's potential, but you're also wasting a precious resource: water. Simply scrape the dishes without rinsing them, then put them in the dishwasher to rinse.
