Painting - Does washing exterior paint really make paint last longer

I've heard that an annual exterior wash will make the paint last longer. Does anyone know if this is a fact? Has it been tested?

I dunno.......... I suppose keeping the paint free of mold or anything that would hold any moisture would make the paint last longer.

Generally I'll only wash a house [besides repaint prep] if there is a mildew/mold problem but the paint is in otherwise great condition.

I can't see any need/benifit to arbitrarily washing the paint every year - only if it needs it to look nice.

The benefit that I have found is that the paint looks fresher after having been washed. I typicallly wash my house every couple of years for this reason. Exterior paint is formulated to chalk somewhat so that the dirt and such is carried away.

Hope this helps.

I'm not sure it makes the paint last longer
But it absolutely make the paint look better longer, and increases the time in between paint jobs

Dirt on the paint can dull and scratch the surface, and mold and mildew that is allowed to live merely grows larger and more tenacious, which means harder to remove and more damaging to the paint when it is removed

Some places there can be other issues, like salt that must me washed off
(not sure where that would be...lol)