A driveway fails from the bottom up. Almost every sunken, rutted, weed-riddled drive we are asked to fix has a perfectly acceptable surface sitting on a sub-base that was never deep enough or never properly compacted. You cannot see it, which is exactly why it gets skimped.
So that is where the work goes: dig out to depth, lay and compact the sub-base in layers, set the edge restraints in concrete, then lay the surface. Edges are the other common failure — block paving with no proper restraint spreads sideways under a turning car and the whole thing loosens off from the perimeter inwards.
The other thing that catches people is drainage. Since 2008 you have needed planning permission to pave over a front garden with an impermeable surface unless the water drains to a permeable area within your own boundary. We deal with that as part of the job rather than leaving you to find out afterwards.