What size T-shirt do you wear

Sometimes the size I order depends on the brand of shirt -- one size is fine and fits perfectly until it's washed and suddenly, uh-oh, not a comfortable fit anymore, so I should have ordered one size larger. Sometimes I buy the size I usually wear and, wait a minute, this one's too big. In other words, I like to know the brand or manuacturer of each shirt so I know what size works for me because, as I'm sure you know very well, they're not all made the same and they don't all wash and dry the same.