Calvin Institute of Christian Worship:

“The importance of individual subjective prayer what prayer does for me has increased in everyone’s mind. But my experience as a pastor is that people don’t actually pray much on their own,” Boers says. Nor do many people’s spontaneous individual prayers relate to the church as a whole.

He explains that common daily prayer provides a link between private prayer and corporate worship.

via Uncovering the Blessing of Fixed-Hour Prayer.