In most climates, you don’t ever need to seal exterior concrete drives and walks. But there are advantages to using a good sealer, and in the long run, you can save money and keep the concrete looking like new.
In northern climates, snow-melting chemicals and freeze-and-thaw cycles can damage the concrete. Salt penetrates the surface and loosens it. Repeated freeze-thaw-freeze-thaw can pop the surface loose.
In warm climates, the concrete faces little risk from snow-melting salt and chemicals, but there can be staining problems. Perhaps your daughter’s boyfriend’s rusting truck or fallen leaves from an oak tree stained the drive. Even dirt in the air can do it. Applying a clear masonry sealer will protect concrete from stains and dirt by sealing the porous surface.
Sealers such as Drylok Concrete Protector will help solve the problem of staining, dirt penetration, and damage due to chemicals. The clear sealer penetrates the surface and seals it from dirt and moisture. Clean the surface with a pressure washer or a strong detergent scrub; then apply the sealer per the label instructions. Often the sealer is used with a roller or rough surface brush on the end of an 8-foot handle.