As a native English speaker, I've mostly been allowed the luxury of pretending that ASCII is enough, and have been able to treat font encodings as not my problem. I've seen lots of advice that I ought to include \usepackage[T1]{fontenc} in my preamble. (See, for instance, p. 337 of The LaTeX Companion.) What isn't really adequately explained is why I ought to do so.
So, if I am writing in English and have to make only occasional use of things like G\"odel, what does following the advice really get me?