If your old driveway is starting to crumble or if it has buckled due to frost heaves, it is probably a good idea to get a new asphalt driveway.. If an asphalt driveway is maintained properly, it should last 25 years or more, so once you do get that new driveway, take care of it so you don't have to get another one put in for many, many years.
All vehicles need to stay off the new asphalt for at least three days after the driveway is completed to allow the asphalt to harden. Vehicles are not allowed to drive or park on it. People may walk on it immediately after it is completed.
To preserve the driveway, have it sealed with a coal tar emulsion sealer. Unsealed asphalt will eventually get too dry and become brittle, causing it tol crack and crumble much easier. Also, unsealed asphalt is porous and allows water to get through, which will unsettle the sand or gravel base underneath the asphalt. When the water freezes it will expand and open up cracks or create frost heaves.
Wait at least 90 days after the asphalt is put down before sealing it. This will allow it to fully cure. Do not wait more than 12 months to seal it.
Replace the sealer when it has worn off. This will be about every two to four years depending on traffic and weather conditions.
When a crack or hole does form in the asphalt, take care of it quickly so it doesn't become worse. Cracks allow fluids in that will begin to open the crack up wider. Potholes or even low areas in the asphalt will allow water to pool, allowing the water to start to wear away at the asphalt.
Holes and cracks that are wider than 1/2 inch should be filled with asphalt cold-patch. You can purchase the material in bags or cans; be sure to read the instructions for using them properly. Smaller cracks can be sealed with crack-filler, which comes in cans, bottles or caulking tubes. However, if your driveway needs to be resealed, the sealer will fill small cracks, so you can just reseal the driveway to avoid sealing individual small cracks.