One should consider the question 'how much worth is my typing?'
If it's "just" your average irc/email among friends/etc, fine.
If it's about "serious business", one might want to consider the
(monetary)
value to other parties. It is possible to spy an old crt from a
very far
distance (a few hundred meters, that's what I've been told to, haven't
seen/used any spy gizmos myself. "Newer" monitors not included,
afaik). I
wouldn't be surprised to find out that some wireless keyboards
could be
easily spied on, too. Paranoid?