Many empirical studies of the use of e-mail have been performed, but longitudinal studies are not common. In this article a longitudinal study is presented, with data collected during 1994,1995, and 1998. The research question was as follows: How does the use of e-mail change over time concerning problems experienced with e-mail, the flow of messages, and time to handle mail (i.e., to send and receive a response)? Results show that the flow of messages was stable (sent mail per day) or doubled (received messages per day). Time to handle mail was stable over the 5 years, but the experienced amount of time to handle mail changed from not being sufficient to sometimes sufficient depending on the total work situation. Experienced problems with e-mail decreased during the 5-year study period. The time for respondents to reply to a message changed during this period from immediately to in a day or even a week. Respondents accepted not receiving replies to their own messages, but they used strategies to get answers to the most important messages.