The church expects members to participate at least once a year. The Lord's Supper is a new covenant ceremony, and it is not restricted by old covenant rules about the Passover. And since the new covenant does not specify when the Lord's Supper should be observed, we are free to make our own decisions about it. It is our policy that members may observe communion as often as they wish. This may be done by small groups without any need for prior approval from church leaders.
Some people think that once a year is often enough.
Other people think that it is not often enough. No, the physical symbols are not absolutely necessary. For many people, yes. That is why Jesus told us to do these things in his remembrance. Many people understand and remember ideas better when they have not just words, but also actions in which they participate.