Yes, it is possible to pave over an existing driveway, but whether it's the right choice depends on several factors. If the underlying structure of your current driveway is still strong, concrete or asphalt resurfacing can be a cost-effective way to prolong its life. However, if your driveway has significant issues like potholes, deep cracks, or other inconsistencies, it is best to remove the old driveway and start from scratch. Key factors to consider include the current driveway's condition, the compatibility of the new material, the added thickness and height, and the necessary surface preparation.

Whether you should resurface or replace your asphalt driveway heavily depends on its condition. If the foundation is solid and the damage is minor, resurfacing is your best bet because it’s more affordable and faster than replacing the driveway. But if your driveway has foundational problems and/or severe damage, like large, deep cracks and potholes, then it makes more sense to replace it. 

You can expect your asphalt pavement to last anywhere from 20 to 30 years, or 25 years on average. The life expectancy of your asphalt driveway depends on the climate, the amount of traffic, and how well you maintain it. While you can’t necessarily control some of these factors, you can control the amount of maintenance effort you put into your driveway. 

To prevent your asphalt from deteriorating prematurely, you should follow a good maintenance routine involving regular cleaning, reparation work, and resealing.

If you miss the perfect time frame to trowel finish concrete, you likely won’t get the smooth, flawless result you’re looking for. In this case, you should contact a concrete professional or look to methods like sanding, grinding, or patching once the concrete dries. These methods will ensure the best final result for the lowest cost.