There is NO magic formula. Glazing or waxing only covers or masks the scratches. A soon as the wax or glaze starts to wear off the scratches will be back. The new clearcoat finishes make it more difficult to tell when your car needs wax. It may need it far sooner than it appears.
Most manufacturers recommend waxing the vehicle at least twice a year.
There are two methods to determine if your car needs wax. If it tends to drag across the surface it probably needs wax. The more drag the less wax on the surface. After washing and drying your car, run your dry palm along the upper surface of the hood or trunk. Again if you detect some drag you need wax.