When you go looking for a family's children in church records, take the time to get an overall picture of the record you're looking at. It might save some time in the end!
Take a look at the christening habits in the area.
Often, children were christened a few days after their birth, but in some communities, it was common to have two or more children of the same family christened on the very same day. The reason is easy: "It's the better value!"
This practice may extend the period of time you have to search. Imagine you already know that the mother was born in 1820, and that the couple were married in 1845. Usually, you terminate your search around 1865 unless you have proof that the wife died even earlier. When you find that in this communitiy, it was not uncommon to have children christened when they were already five years old, be thorough and extend your search accordingly - the couple might have put off the youngest child's christening just in case they'd have another little one.
You might regret it later if you don't.