There are a lot of challenges that you would face over the course of your life, but cleaning your driveway is going to beat all of them for the most part. This is because of the fact that driveways are usually ignored as far as cleaning is concerned, and that means that they eventually become dirty enough that they are no longer usable. The most terrible disadvantage to not cleaning your driveway is that it would sustain some massive damage and get cracked beyond belief come winter, so cleaning it in the summer when you still have time can be a useful thing to add to your list of things to do.
The truth of the situation is that when you power wash, you will get rid of the vast majority of dirt that it had on the outermost surface. That might lead you to believe that the job is done, but you should remember that the extended period of not cleaning the driveway means that you will still have an extremely long way to go, and that is if we put things mildly.
You should spray a diluted mixture of dish washing soap and water which is hot enough to make the surfactant dissolve on your driveway before pressure washing it. Diluting it enough allows you to spray it, and the fact of the matter is that this is less time consuming as well as a lot more effective than spreading it on through any other means. You can also find a lot of sprays that have been custom made in factories, all of which are uniquely suited to driveways and the cleaning that they require.