It's usually usable within a day, but it stays soft for a while and keeps hardening for several weeks. During that period, avoid turning your steering wheel while stationary, don't park a jack or a trailer leg on it, and keep motorbike stands and other heavy point loads off it. Most early tarmac damage comes from point pressure in the first few weeks, not from driving.
Standard tarmac isn't permeable — but porous asphalt is, and you can also lay standard tarmac and drain the run-off to a soakaway or border within your property. Either route keeps you within permitted development. Laying impermeable tarmac over five square metres in a front garden and letting it drain onto the road is the one thing that triggers a planning application.
A properly laid tarmac drive on a good sub-base will give you many years of service with very little upkeep. The main enemies are tree roots, standing water and fuel spills, which soften the bitumen. Keeping the edges properly restrained and the drainage working does most of the work. It can be sealed to refresh the colour, though that's cosmetic rather than structural.
