When to launch a new faith community is a question that must be carefully considered by the church planter. To launch too early will mean quick and almost certain death for the church planter's and God's dream for the new faith community. To take too long to launch means losing or never gaining momentum. Thus there has to be a middle way- a via media.
I have found three main ways of thinking about when to launch. First and probably the oldest suggested launch date was Easter Sunday. How symbolic to launch this new work on the day of resurrection. After all, Easter is so well attended and unchurched people are more willing to attend church on Easter than any other Sunday. The drawback for an Easter launch is that the Sunday after Easter is one of the least attended Sundays and you quickly find yourself in the middle of the doldrums of summer.
Another school of thought says to take your time launching and spend about 15 months working the mission field, preparing your church systems, putting ministries in place and gathering as large a launch team as possible. For United Methodist people this would mean launching in September a year after one is appointed. The drawback with this approach is that the longer you get out the harder it is to sustain momentum and one must be especially strong to avoid the call to begin weekly worship and avoid the notion that once you start a bunch of people will automatically come and they are just waiting for you to start.
A third way that I have heard articulated recently which I really like is to consider launching in February. For UM people this would about 8 months after being appointed. This is a good time of the year to launch especially after Super Bowl Sunday. Persons are not as busy with spring or summer and you get a natural bounce come Easter. 8 months is enough time to put systems, ministries, and other essentials in place and to gain a launch team without losing momentum.
Whenever a church planter decides to launch they must obviously listen for God's direction. However, they must ensure that it is God's direction and not their own or a chili dog giving them heartburn that they mistake for the leading of the Holy Spirit.