Should I change how my email or newsletter template looks each month?

Should I change how my email or newsletter template looks each month? I got this question recently from two different clients who had both received similar advice.  One was asking about general email templates, and the other about newsletter email templates. ... Read more at http://vickywu.us/should-i-change-how-my-email-or-newsletter-template-looks-each-month/ #marketing