Just as you are required to regularly clean your house, it is also the same for the driveway. If you regularly clean the driveway, pressure washing should be something common that you do.

Dirt and grime can accumulate over the months not just in the cracks, but also the entire surface making the driveway look dirty. In additional to looking bad, sometimes you can find the driveway being a health hazard or cause structural harm.
Most professionals advise that you should pressure wash your driveway at least once a year. To help keep the grime and dirt off the surface, you might want to consider pressure washing the driveway every four months. This should be enough to maintain its look without degrading the integrity of the concrete surface.
Factors affecting how often you should pressure wash the driveway
The climate and environment
For most people, this is going to affect a lot how often you wash the driveway. If you are in an area with many trees, plants, humid environment or one that is subject to rain, then you should consider getting the driveway pressure washed more often. With a humid environment, the chances are that you might end up having algae growing in the cracks. With a proper power wash, you can clear them with ease.
Health consideration
Well, the health of your family members is important. If any of your family members suffers from asthma or any other allergies, then it is best to power wash the driveway to avoid the spreading of the harmful molds, bacteria, and any other organisms.
Planning to sell the property
For those who are planning to move out of their homes, having a clean surrounding can boost the value of the property. It is why you might want to clean your driveway as it is the first thing that the buyer sees when they are looking to get a house.
Personal preference
As suggested earlier, you can clean the driveway once a year. It does not mean you cannot clean more often. Based on personal preference, you can clean the driveway more often to ensure it maintains its look.