To maximize effectiveness, a discipleship group should meet weekly. Groups that meet two times per month rarely gain the traction necessary to form
accountable relationships
among the members.
Since it is rare that every person attends every meeting, it is vital that there are weekly meetings. Hopefully, your members will be able to attend at least 3 out of 4 weeks in a given month. Then they can form meaningful relationships and stay connected with each other.
Keep the goal in sight
The goal is to become like Christ. This requires accountable relationships -- and that takes time. Pay whatever price is necessary to meet weekly. The sacrifice is worth it.
Meet for two years
In general, I believe the appropriate time frame for a small group is two years. I'm not suggesting that no one in the class can stay together, but that it divides into 2 or 3 groups. This offers a chance for new people to join. New leaders are developed.
Keep reproducing
Healthy organisms reproduce. Multiplication is a clear expectation of
discipleship.
Maturity must lead to multiplication.
Most Christian small groups stay together too long simply because no one explains, in advance, the intention to meet for a specific period of time - for a specific purpose. It becomes awkward for anyone to leave. When groups stay together too long, the group tends to become a
"fellowship" group
rather than a discipleship group. The expectation to multiply is lost.
Let's suppose you are going to start a new discipleship group around Labor Day. If you meet weekly until Memorial Day (allowing for breaks around holidays) your group would meet approximately 30 times.
Furthermore, let's suppose that your group meets about 5 times in the summer to maintain a sense of connection. If that format is repeated over two years, your group will have met 70 times (35 times per year).
Seventy formal sessions is enough time to teach the members of your group the spiritual disciplines of reading Scripture, confessing sins and praying for the lost.
Your Christian small group
Think about your small group. At the beginning of the year, could you share with them your heart to see:
Ask if your group could meet weekly for two years, then multiply into at least 2 groups. During these two years, consciously pray for and develop at least one leader from this current group.