Does it matter what day of the week you send your email marketing? According to a new survey—yes.

The Delivery Trends Report from EmailLabs, a provider of email marketing automation solutions, found that Tuesday is the most popular day for companies to send emails and Wednesday is the top day for recipients to open emails.

Why Tuesday and Wednesday? For years the conventional wisdom has been to not email on Monday (the first day back in the office) or Friday (end of week deadlines, leaving early, etc.). In addition, unless the sender is targeting an appropriate consumer audience, weekends are out. Also, from a practical perspective, marketing teams often complete the email creative and production process on Friday or Monday, hence Tuesday or Wednesday distribution.

“The most obvious implication is that during the middle of the week your email messages are battling with a greater amount of legitimate email than on other days,” says Loren McDonald, VP of Marketing, EmailLabs. “Flexibility remains essential. Depending upon your content, the relationship you have with your recipients, who they are, the frequency of your emails and other factors, days other than the middle of the week may in fact generate better results.” In other words, try Thursday.

In a second major finding, email recipients are tending not to "unsubscribe" from emails, which shows a steady decline in unsubscribe rates since January. Rather than officially unsubscribing, recipients are now more likely to simply delete unwanted emails. Accordingly, many email marketers are now eliminating names of subscribers who do not open a specified number of emails in a row, or are asking those subscribers to re-opt in.

“Email marketers should always watch their unsubscribe rate closely, but if it is, in fact, declining for your company, don’t assume that you have a higher retention rate,” says McDonald. “Make sure your unsubscribe process is simple and functioning, and instills a sense of trust. Second, consider weeding out in-active subscribers from your list. For example, ask subscribers that haven’t taken any action over a specific time period to re opt-in.”