There is no right answer, because that is dependent on every church.
Here are some general guidelines:
1. When your people are ready to grow. When people care more about personal preference than growing the church, you’re not ready.
2. When a church is healthy. If the church is divided spiritually, a physical separation could be very harmful.
3. When there is enough mass. You can discuss percentages, breaking points and all types of numerical truths. However, when it’s not embarrassing to have two services in your space, then it’s time to split. (Note: lots of churches, including Elevation Church in Charlotte, have been successful at draping off part of their sanctuary during multiple services that have lower attendance).
4. When you know how to manage a service. If your people aren’t used to tight, efficient (but powerful) services, then they will have a hard time adjusting. Some people equate powerful services with lengthy services. To counter this incorrect mindset, I started increasing our efficiency in our one service months before we split to two. This helped people adjust their expectations, and it helped our programming team and altar team adjust accordingly.
5. When God says so. I had felt for months that God wanted us to make this move, but there were always pros and cons. Ultimately, as the leader of this flock I had to obey God’s leading. With all the different voices on multiple services, don’t forget to hear the ultimate voice. What does God want you to do?