[Flanderian]

The answer to your first yes or no question is, yes. But the answer to, does it shrink it every time, is no.

It's not a simple issue because different cotton shirts react differently, and those treated to be wrinkle resistant hardly shrink, if at all. And even those that aren't can shrink anywhere from unwearable to unnoticeable when subjected to the same treatment.

I've always laundered my shirts myself. I've done this for about the last 40 years, or so. I launder them in warm water, and machine dry them. All untreated shirts will shrink to some degree. If they shrink to the point where it's a problem, they were either too small to start with, or the cloth is, IMO, defective.

Most of the shrinkage occurs during the first cycle of laundering and drying, and sometimes continues for the next one or two, but to a much lesser degree. Most of this shrinkage occurs during the machine drying.

When I had a shirtmaker, he estimated an average shrinkage of 5% and cut his shirts accordingly, and I never had a problem. But of course, if shirts are purchased to resemble shrink-wrapping from the start, it could be a possible big problem.

 

[Flanderian]

This agrees with the views and practices of my alterations tailor. She wants cotton chinos and shirts cycled once through hottest wash and hottest dry before she takes over. I have no experience with altering polos or anything else knit.

Knits can be scary. Depending on the fiber and how it's knit, some of them can shrink up into doll clothes, others don't have much of a problem.