My boss writes long emails. How long should an email actually be?
Follow the 30-second rule. It should take your reader 30 seconds or less to get the point of your email. You should include the main details of what you want to convey without getting swept away with filler information that can be seen as unnecessary or confusing to your reader.
Long emails can be overwhelming, leading her to either flag the message to read at a later date or simply quickly skim the contents. These actions can lead to a delayed response or one that does not fully address the email in its entirety, which is something you have probably experienced with your boss.