Mill it before you lay over it
Asphalt milling takes the worn surface off a road or lot down to a set depth. Skip it and the new mat goes right over every crack, rut and high spot already there. The surface climbs a little higher with each overlay, and the curb reveal and drainage that were built into the street slowly disappear.
Milling puts the grade back where it belongs before any new asphalt is placed. The milled material can be hauled off and put back to use instead of buried, so you are not paying to bury a surface that still has value.
