The church of Christ observes the Lord's Supper as a poignant, yet simple memorial. Paul declares, " For I received of the Lord that which also I delivered unto you, that the Lord Jesus in the night in which he was betrayed, took bread; and when he had given thanks, he brake it, and said, This is my body, which is for you; this do in remembrance of me. In like manner also the cup, after supper, saying, This cup is the new covenant in my blood: this do, as often as ye drink it, in remembrance of me" (I Cor. 11:23-25) "In remembrance of me" is mentioned twice above and once in Luke 22:19-23. It is in his memory that we take of the supper.
Whenever we partake of the Lord's supper we are compelled to remember Christ's death and what it did for us. (I Cor. 11:26) In like manner, our remembrance serves as a reminder to the world that Christ died for them.
What about the regularity of partaking? In Acts 2:42 the Church at Jerusalem continued steadfastly in the apostles' teaching and fellowship, in the breaking of bread and the prayers. This indicates a regularity and frequency and not an occasional custom.
The church at Troas came together on the "first day of the week" for the purpose of breaking bread. (Acts 20:7) The church at Corinth partook of the Lord's supper when they came together. (I Cor. 11:20) and they came together on the first day of the week (I Cor. 16:2) Does this mean every first day of the week? A universally, understood commandment from the Old Testament can answer that question. God said, "Remember the Sabbath, to keep it holy". That was and is today understood to be every time the Sabbath rolled around- Every week!
Only members of Christ's church can partake of the Lord's supper. Luke 22:29-30 says, "And I appoint unto you a kingdom, even as my Father appointed unto me, that ye may eat and drink at my table in my kingdom." Are you partaking "unworthily" if you are a sinning member? Considering that there was only one who had no sin - Christ Jesus the Righteous - we as humans, who are prone to sin and failure, must (despite our condition at any given time) do as commanded. This is not an option. "Unworthily" is a term that refers to the mindset of the participant at the time. We must think of Christ and His sacrifice (worthy thoughts indeed) as we commune with him.