Talk about the kinds of wheels on a car. There's the steering wheel, then there's the back tire. What is prayer to you? Is it the steering wheel that you use every time you drive, or is it the back tire that you just use sometimes, only when you need it.
Ask if you should pray only when you need it, like the spare tire, or all the time, like the steering wheel.
After determining that prayer is like the steering wheel, the one you use all the time, talk about the reasons to pray.
Remind them that it's important to pray all the time. When things are good and when things are not going well.
Ask the children what things they have prayed about.