Almost immediately after paving, the sun goes to work daily, drying out and oxidizing your pavement and making it very brittle on the surface. 

The binder which holds the stone and sand together is called "liquid asphalt" which hardens to a relatively soft consitancy and its always the first to fail.

Once the liquid asphalt wears the pavement starts to ravel.  Ravelling means the stones and sand particles that make up the pavement begin to jar loose.  These loose stones and sand act like sand paper and combined with vehicle tires, flowing rain, sprinkler water and wind, can erode your pavement at a very fast rate.

Asphalt Sealing not only blocks the sun and its harmfull rays but it also helps to rejuvinate the asphalt by replacing the binder that it so desperately requires for a long life.

Sealcoat acts like a winter coat keeping the heat in and elements out.

Water

Unsealed pavement allows water to penetrate through the asphalt.  This water penetration is the source of rapid deterioration particularly in the nothern hemisphere.  Regular water penetration from rain and sprinklers can cause the sub base to erode and become unstable, ultimately leading to complete pavement failure.  Sealcoat helps to prevent water penetration by sealing the small cracks and pores.

Snow & Ice

In winter the water goes through freeze-thaw cycles which heave and compress the pavement leading to the development of potholes and eventually complete pavement failure.  Snow and Ice not only provide dangerous conditions for vehicle and pedestrian traffic, but also hide all of the important info such as pavement markings and line painting that people require to use the lot safely.  Sealcoat assists in the melting speed of snow and ice with its dark black color.  It stays warm before the snow and heats up fast after it snows.  

Salt

Salt that is strewn about on pavement acts like sandpaper and can erode unprotected pavement. Sealcoat provides a hard durable surface that helps to mitigate excessive wear from salt granules. 

Most vehicles on the road today are no older then 10 years old and do not commonly leak fluids.  As more and more electric/ hybrid vehicles hit the road, fuel, anti freeze and oil will also be a thing of the past.

With that said, some older vehicles still do leak fluids and some fluids can damage asphalt permanantly. Sealcoat provides a layer of protection against fluid leaks.