We store detailed information for delivered messages for 30 days. Bounced message data is kept for 90 days for record-keeping purposes. This information is available on the Activity page of your Mandrill account and includes details about the subject line, sender, recipient address, total opens and clicks for the email, and metadata.
Overall statistics (total deliveries, bounces and rejections, along with unique opens, unique clicks, total opens, and total clicks) are stored indefinitely. View these overall stats on the Dashboard or using the senders, tags, and templates API calls.
Mandrill will temporarily keep a copy of the HTML and text portions of emails sent for your account, allowing you to view the email content and resend messages.