There's a two stage cycle to church growth - grow it and preserve it; grow it and preserve.  It's also call the salt and light stage (Mt 5:13-14).

1. Salt Phase

The goal of the salt stage is to preserve the growth that you've gained and to keep your saltiness (flavor).  Don't compromise your message, don't compromise your outreach, don't compromise your leadership development, don't compromise the presence of God.  Hold your ground.  You may not be going forward, but don't go backwards.  It's like a family that has stopped having kids.  They may have stopped growing numerically, but it doesn't mean the family starts stagnating.  On the contrary, they are still called to be vibrant, healthy, a witness and world changers. 

Church growth is a funny thing.  It's partly based in God's sovereignty (the seasons of God, what the spirit of God is doing in a city, country, culture), and it's partly based on our calling and talent.  But it's God who frames the picture.  We work inside of it.  God has his seasons of breaking out and his seasons of preserving.
 

2. Light Phase

This is the breakout, breakthrough phase.  It can be called revival, renewal, reformation.  It can occur  on a mini-scale (one church) or grand scale ( multiple churches, a city or a country).   This is where the church grows numerically, where salvations are registered in great or steady volume on a regular basis.  This is exciting stuff.  But there comes a time where the church either needs to take a pause or plateau for awhile to catch up to the growth.  It's like someone needing to come up for breath.    Theoretically you build infrastructure to stay ahead of your growth curve, but in practice this doesn't always happen.    The momentum and excitement generated in this phase is what all church planters live for.

Generally speaking, you can label the salt phase as the pastoring phase, and the light phase as the pioneering phase.  Jesus was both the Great Shepherd and Great Apostle.    Understanding the dual nature of church planting helps us manage our expectations, stay healthy and cooperate with each season.