As convenient as dishwashers are, not everything should go through them. Some items are much better to wash by hand in order to protect them from damage.
Good quality knives, for example, should be washed by hand. Running them through the dishwasher can dull or damage their blades. The same goes for wooden utensils, which can warp and crack in the heat and moisture of a dishwasher.
Cast iron and non-stick pans should also be washed by hand to preserve their finish and non-stick qualities. Similarly copper or brass pots can be damaged and suffer discoloration in a dishwasher.
Sterling silver cutlery and anything with gold plating can have its finish worn away by dishwashers, and contact with stainless steel can cause a chemical reaction in your silverware, leaving them discoloured.
Crystal and fine glass can be etched or cracked as a result of the dishwashers cleaning process while insulated mugs can have the seal broken, allowing water to seep into the double wall, ruining their insulating quality.
In general, it’s always best to check the manufacturer’s recommendations before running things through the dishwasher