Blessings are among the most versatile cards in the game. Most can be used to add to checks or to explore again. So when you're blessing your companion's check to acquire a wand, you might be wondering, "Did I just cost us a turn?"
What is the opportunity cost of not exploring? Do you need that sword more than you need to find the villain? The risk-reward analysis requires some thought.
Early in the game, you might be willing to spend a blessing on a check, but when the hourglass is running down, conservatism is often the wiser course. If it's your combat check and you think you need the blessing to succeed, it's likely worth playing it. Fail badly enough, and you might lose the blessing to damage anyway.
This analysis is worth going through, but don't let it stop you from acting. There are always more turns - at least, until there aren't.