The t-shirts are preshrunk cotton, so they do not normally shrink unless you use too high of a setting on the dryer. Typically running the first wash in cold water and using the delicate setting will help keep the sizing truer. As for hoodies, they tend to be a little sturdier. You might see a little shrinking right out of the dryer, but they will generally bounce back into shape after being worn for a bit.  Please see the washing instructions on the tag of each shirt for the best guidance for that item.