There is no such thing as 'prayer surplus' when planning a mission trip. We encourage a Ten To Pray ideal. Ten friends and family to institute, 'Don't worry about anything, pray about everything' Phil 4:6. This grafts others into the mission branch.
Here is an example of faithful prayer:
Upon our return from Ghana, Anna approached us to say she had been praying through Psalm 91 while we were away. It begins beautifully with, "Those who live in the shelter of the Most High will find rest in the shadow of the Almighty".
The verses she felt compelled to repeat were, "For He orders his angels to protect you wherever you go. They will hold you with their hands to keep you from striking your foot on a stone. You will trample down lions and poisonous snakes…."
She could not know that we had come within 2 feet of a python: 6 inches in diameter and about 5 feet long, while walking down a dark lane in the night time towards the main road in Amrahia. Anna is one of our Ten to Pray. She has prayer journeyed with us for 10 years.
She is a faithful friend; we serve a faithful God.