This depends on whether the house has mildew beginning to grow.

If the quality of the paint is good you may not need to pressure wash until the next paint job.

If the house mildews in the fourth or fifth year it’s because the paint is breaking down. If you wash the house at this point it will only last about one year before the mildew begins to return. It’s probably a good time to think about painting again.

If your house has had good paint which contains a quality mildewcide you should be able to go eight or ten years depending on the sun and shading of the house.

It is best not to wash your house every year. The reason to wash a house is if it becomes dirty or has accumulated mildew. It’s a rare occurrence to have a significant accumulation of dirt unless there is new construction nearby. So mildew accumulation is generally the only reason to wash a house.

Traditionally you pressure wash your house using bleach. Sometimes you choose an additive that is designed to mix with bleach to help clean the surfaces. This process is slightly corrosive. It will break down minutely the paint film, and accelerate any potential rust almost immediately ( nail heads and galvanized gutters and other, ferrous metal surfaces.)

How should I maintain my house in between paint jobs?

You should rinse the sofits and areas that do not get washed by rain with a garden hose each spring. This will help dissolve salts that crystallize as humid surfaces evaporate.

Dissolving the salts helps reduce dirt buildup.

You might elect to paint the gutters which after 4 to 5 years, they  usually have black streaks as result of debris accumulating in the gutters and run over after a heavy rain  (the factory finish is usually wearing thin).  Sometimes these stains are from mineral stains from water that’s sitting on top of the gutter edge or from inside the gutter.

Maintenance painting of certain areas of the house might be needed. For example first floor window sills, porch handrails, stair cases and fascia boards that are exposed more to weather than other parts of the home.