It's a good task to remove inactive subscribers from your list here and there. People who aren't interested in your message and opening your emails are not valuable anymore to you. They also may forget who you are and mark your message as spam... How often you need to clean the list or how long need to be enough to delete inactive subscriber from your list..... The amount of time that passes for a given subscriber to stop being an asset and start becoming a problem will vary depending on your...