The following is a guest post from SendGrid’s Compliance Desk. The most common problem that SendGrid customers encounter is also the easiest to fix. Sending to old, unengaged email lists means more messages marked as spam–or worse. We understand that is it hard for a business to forfeit potential customers, but sending to an old address list has the potential to trash your email deliverability and completely ruin your brand name. So let your old email addresses rest in peace! Three key factors used in deciding whether email hits the inbox are spam traps, bounces, and spam reports. Too much of any of these can negatively impact your sender reputation. And all three can be caused by using old email lists. Spam Traps are old addresses (or even entire domains) that have been abandoned then recycled into ways to spot bad senders. Spam traps never opt to receive email, so anything sent to them is certainly spam. So while an address may have opted in years ago, the spam trap just sees spam. Bounces are when an email is sent to an address that no longer is accepting email. Old addresses that have been taken out of commision will likely result in a bounce. Receiving mailboxes monitor how many bounces you have on their system and will reject your email if this volume is too high. Spam Complaints tend to be the most common thing sender’s think about, but often only related to the content of a particular email. A recipient who is no longer interested in your email (and may not even remember opting in) is much more likely to report your email as spam, regardless of the content. The above three email no-nos can become accidental practices of good senders. Prevent Bad Sending The good news is that there are a number of easy ways to make sure you’re only sending to recipients that want your message. Remove the unengaged from your lists. If someone hasn’t opened or clicked your email in the last six months, for example, they are probably not interested in or expecting to receive your emails. Make sure you’re getting opt-ins. We hope this seems obvious, but you want to explicitly get a recipient’s permission. Double opt-in is preferable as it also verifies you are sending to a legitimate address. Consider a re-opt-in. Don’t rely on them to unsubscribe. Using our Event API, check to see if they are clicking or opening your mail. If not, send them a winback email and follow these best practices regarding your reconfirmation campaign. Ask for their new address. Address turnover rates are around 30% per year. Put a form in place that makes it easy for subscribers to notify you that they have changed their address. Make unsubscribing easy. Make sure your unsubscribe link is always very visible and easy to use. Remember that you are competing with the “Report Spam” button for ease of use. Don’t send to bouncers. SendGrid automatically suppresses all previously bounced, blocked, spam reported, unsubscribed, and invalid emails under your “Email Reports.” Be safe and remove these addresses from your master list. Most importantly, keep in contact. Continue engaging with your subscribers, keep them updated, find clever ways to keep them interested. This way you will be able to see their engagement over time and they won’t forget about you–and mark your email as unsolicited spam. When it comes to list housekeeping, a little effort in the short term can go a ways in the long run and will save you a lot of headache. After employing these methods, you will have a great reputation with receiving mailboxes giving you better deliverability and higher engagement rates. Besides, nobody wants to be known for sending spam.