Depending on how you take care of it it should last 12-15 years before it should be paved again.
Mother nature has a big effect on asphalt. Cold winters and hot summers as well as vegetation, tree roots, over weight vehicles and just plain neglect has a part on your asphalt longevity.
Sealcoat it at least every 3 years. Watch out for oil/gas leaks/spills, cracks, vegetation growth and over weight vehicles. If you address those problems as soon as you see them then you will avoid a costly repair and maybe even having to repave.