Most exterior surfaces do not need replacing. They need the ten years of algae, traffic film and oxidised grime taken off them, at the right pressure for what they are made of.
Pressure is not one setting
Concrete takes a lot. Interlock takes less, and too much strips the joint sand out and leaves you with a bigger problem. Vinyl siding and painted wood want a soft wash — chemistry doing the work at low pressure, not force. Using driveway pressure on siding is the most common way a cheap wash turns into a repair bill.
Organic growth comes back unless it is killed
Blasting green algae off a north-facing patio makes it look clean and does nothing to the spores. It is back within the season. Pre-treating first is what makes the result last, and it is why a proper wash takes longer than a quick blast.