Unfortunately, we can’t give a blanket answer to that question. IMPRÄGNOL impregnation sprays offer long-lasting protection against wetness and dirt. But waterproofing always wears off over time, so a jacket that’s exposed to the elements every day will need to be waterproofed again sooner than a fair-weather shoe. Simply do the water droplet test: allow a drop of water to drip onto the surface. If it runs off, the item is still waterproof. If the water is absorbed, it’s time to reapply the impregnation. By the way, items need to be waterproofed again after washing or cleaning.