Asphalt:
You can't fix cracks. They always reopen. You can patch any pothole if you repair what's soft under them that caused the hole (subbase failure). Normal paving useful life is about 15years. Sealcoating and crack repair may give you 5 years more of useful life. You may get away with a new 1" dressing topcoat for not much more than sealcoating, and put off the seal coating for 3-5yrs. Generally, if the paving is still at the levelness (no vertical displacement on the cracks, and there are few/no potholes, I'd put a new top coat on, preceded by chasing out the cracks to remove all loose stuff and leave a big enough gap to fill with crack repair compound, plus a tack coat all over. Surface must be VERY clean. Be aware that putting down a new dressing coat will leave a small hump going down into the garage, if any. Cutting out 3-4' of asphalt there gives you room for a reasonable taper into the garage. I hope it's not downhill down the drive into the garage...
Asphalt has several enemies. road ice, water penetration to the sub base, sun, and traffic. asphalt is petroleum based asphalt cement (a very heavy tar that melts around 130*f), sand, and crushed stone aggregate of varying size depending on mix specs and final use. It has very little tensile strength, much less than concrete, and is really just a modified sealer of the surface to keep moisture off the earth sub base, which will soften when wet, deform under load, and let the asphalt and rock base above come apart in a pothole. Cracks are due to age (progressive hardening/brittleing of the surface due to loss of volatiles over time and polymerization due to sun and ozone and road crud, and/or sub base movement such as settling fill, or root intrusion. I like to trench along every asphalt surface to a depth of around 2', and line the side of the trench with visqueen sheet plastic to block root intrusion. Some salt in the trech is good, too.
Concrete:
You can't fix cracked concrete, only demo it and repour. If you have no vertical displacement, it's possible to do a 2-3" cap pour in concrete if you use something to break the bond between new cap and old pour, like geotechical fabric, a coat of sand, or visqueen plastic, which may or may not let new cracks open up over old ones, or cap the concrete with an inch of asphalt and tack coat, but the cracks in the concrete will show up in the new asphalt. It is possible to cut concrete cracks out wider (at least 6") and pour patches, especially if you dowel/epoxy rebar into the old surrounding slab edge and tie to new rebar in the crack, thus tying new to old vertically. I like to add a touch of hydraulic cement to the fill mix, as it swells slightly on cure and will lock new to old that way.
The most important part of pouring concrete to avoid cracking is not to avoid it, but control it, like perforations in toilet paper. You diamond saw cut 1-2" deep control joint kerfs in the new pour within 3 days of the pour, in a pattern which leaves no more than 100sf of concrete inside a polygon of cuts. In a driveway, unless it's wider than 10', you need a joint across the drive every 10'. The crack will (mostly) occur at the cut. Concrete cracks for two main 1usually reaches 90% of rated compressive strength (usually 3000psi) by 28 days after pour if kept sealed, and will increase in strength for around a 100years, after which time it will begin to lose strength and revert to sandy/gravelly components. Concrete will benefit from a sealer every 2-3 years after the final cure (follow directions, but a couple of months is good for the first coat) to avoid water penetration of the concrete and resulting spalling of the surface on freeze/thaw.
Both MUST have a properly compacted earth sub base, to what's called 95% Standard Proctor compaction (damn hard) such that the surface does not sink, then rebound under the load of a tandem dump truck tire (pumping). Tighter is better.
A minimum concrete slab is 4" nominal, usually around 3.5" since it's formed with usually 1x4 nominal lumber (3/4" x 3 1/2" actual). A minimum asphalt driveway is 4" of compacted crusher run stone base (rocks from 3/4" down to rock dust in standard proportions) capped by 2" of top coat. Better is 6" of CSB rock, with 1.5" of type B asphalt binder course, topped with 1" of type f or g topping.
Get a certificate of insurance from the contractor's insurance broker for work. comp and gen. liability and non-owned auto BEFORE they start work. Written contract, and READ IT. Get lien waivers in proper form for your state from asphalt plant, truckers if hired out, and the contractor BEFORE you pay a dime. No money up front. No payment for unaccepted work, but get the lien waiver BEFORE you tell him...
