if you use the skill, you don’t need “problem of the day”.
But suppose that you use a skill only occasionally. Then you still need the skill. But to retain a skill, you might need to use it frequently. Therefore, you might need to inflate artificially how often you use it, so that you retain it. That is how it can be that you use a skill and yet still need a “problem of the day”.
You wrote
But suppose that you use a skill only occasionally. Then you still need the skill. But to retain a skill, you might need to use it frequently. Therefore, you might need to inflate artificially how often you use it, so that you retain it. That is how it can be that you use a skill and yet still need a “problem of the day”.