Using the Propper F4521 boots is easy. Just zip up the side zip or use the NATO speed lace system to secure them on your feet. These boots are great for all-day wear, whether you're on duty or in a tactical situation. For maintenance, keep them clean by wiping off dirt and debris regularly. If they get wet, let them dry naturally away from direct heat. You can polish the full grain leather to keep it looking good. When it comes to sizing, they're engineered with true US sizing, so pick the size that fits you well. And remember, these boots are tested and approved by NTOA, so you can trust their quality. Avoid using harsh chemicals on them as it may damage the materials.