One prayer that asks for everything a Christian life needs, from belief to a good death.
A long, complete prayer attributed to Pope Clement XI that covers belief, hope, love, sorrow, duty, and death in a single sweep.
When: When you do not know what to ask for, or as a Sunday prayer for the whole household.
Why: Most days a person prays for the one thing pressing on them. This prayer widens the ask back out to the whole of a life, which is why it has been given to converts and to the dying alike.