The shrinkage of jeans can vary depending on the brand, fabric composition, and construction techniques used. While some jeans may shrink when washed on a hot cycle and dried without tumble drying, it is not a guarantee that all slim fit blue jeans will shrink under those conditions. Different brands may use different materials and manufacturing processes that can affect how much the jeans shrink, if at all.
To determine the specific shrinkage characteristics of a particular pair of jeans, it is best to refer to the care instructions provided by the manufacturer. These instructions often include recommendations for washing, drying, and ironing the jeans to help maintain their original fit and minimize shrinkage.
If you are concerned about potential shrinkage, it is generally safer to wash jeans in cold or warm water and to air dry them or use a low heat setting in the dryer. This can help minimize the risk of excessive shrinkage and maintain the desired fit of the jeans.