It’s not only important to have sharp knives, you should also keep them clean.
Don’t wash your knives in the dishwasher. Even if a manufacturer touts its knives as being dishwasher safe, it’s best to hand-wash your knives. The rough agitation of a dishwasher can damage the blade by knocking it against other utensils or dishes. What’s more, the harsh detergents and high heat used in dishwashers can deteriorate your blade. And finally, it can be unsafe to keep sharp knives in the dishwasher; you could accidentally cut yourself reaching into the racks.
Personally I recommend that you wash knives by hand and dry them immediately. It’s not hard to do. Just use a sponge or dishcloth and warm, soapy water to wash the blade and the handle. Rinse it afterwards with warm water and immediately dry the knife with a dry dishtowel.
Best to wash knives immediately after use.
For practical reasons, a knife is easiest to clean right after it’s used, before juices or food particles have a chance to dry on the blade.
If you’ve used the knife to cut acidic foods like tomatoes or citrus fruits, those juices could corrode the metal or cause spotting.
Letting knives sit in a sink or a basin of water is also a bad idea – you could cut yourself reaching into the water.