I don’t think the Bible mandates how often we are to take the Lord’s Supper. It seems as if the early church observed it every Sunday, though we can’t be totally certain about that. In evangelical circles it has often become an “after-thought” in our worship, to be observed once a quarter or something like that. My own judgment would be that we should observe the Lord’s Supper more often than we do–and pastors should preach and teach about it more than they do because in remembering the death of Christ, we proclaim the heart of our faith. It is to be observed by the followers of Christ until he returns.