The more tightly closed the area you plan to protect, the better. Try to limit the amount of moisture coming into the area so the silica gel doesn’t adsorb moisture from outside. If there is moisture from outside the area you want to protect, your silica gel will become saturated much more quickly and require more frequent reactivation. Limit the air flow into the area as well as the number of times you access the area. For example, silica gel will work well in the inside a storage trunk, but it will not work as well if you are opening and closing the lid of the trunk several times a day allowing moisture from the outside to penetrate.