It may seem risky to suck up the leaves in your gravel driveway. But the task is simple. Remember, rocks weigh more than leaves. Your leaf vacuum only needs to be powerful enough to suck up the light leaves.  If your leaf vacuum has an adjustable speed system, make sure you suck up the leaves on the lowest setting. You don't want the leaf vacuum to be so powerful it sucks up the heavy rocks, but you want it to be powerful enough to catch the leaves. Rocks can cause significant damage to some leaf vacuums, so it's best to start slow. Adjust the leaf vacuum to the lowest setting and test out a small section of the gravel surface to ensure the vacuum won't suck up rocks.