Many email marketers measure their success by the number of addresses in their email marketing lists. To a great extent this is true. The more names one has the greater the chances of the click-through and a purchase. Who could argue against that?

In fact, quite a few people will. Managing your email marketing lists is vital. If you retain dead addresses then the data you obtain from your returns, and on which you will base future campaigns, will be tainted. If you cannot depend on the statistics then there is little point in collecting them.

If you change the time of sending your emails, say from a Friday to a Wednesday, or from two weeks before an event to one week (never two changes at the same time) then you will peruse your returns closely to see if it gave any advantage. A percentage or two is a reason to rejoice.

If you have a number of dead email addresses on your lists then any advantage will be diluted. A few here and there will not matter but research has shown that around 20% of those on email marketing lists will change their contact details, including addresses, each year. Your figure will probably differ to an extent but there will be drop out.

• So you need to do some spring cleaning. How you go about this is down to you, but subscriber generated action is normally recommended. 
• Set up a trigger. If a customer does not open an email for a set period, which will depend on your product and frequency of campaigns, then you should take some action. 
• One essential is to ensure that the customer’s history does not show that they, perhaps, merely open emails after a certain trigger. If you sell wine then a few weeks before Christmas might be the wrong time to remove a suspect.
• Send an email asking them if they wish to stay on your lists. It can be passive, asking them to click to unsubscribe, or passive, where inaction is all that is required. The latter is the favourite.
• Do not look upon it as a subscriber lost but confirmation of the dependability of your data.