I wash the windows in my house every 3 years or so, whether they need them or not.
MANY, many months ago, a neighbor told me about Windex Outdoor Window & Surface Concentrated Cleaner.
It ain’t cheap – a 32 ounce bottle cost $10.99 at the local Aubuchon – but what a fantastic product.
It comes in a container that attaches to your hose, like some pesticides. You rinse the window, switch the dispenser to “Clean”, then rinse the soap off.
It works through screens as well, and it isn’t necessary to squeegee, although they do recommend it if you have hard water.
One container seems to be sufficient to do a whole house, including a slider and a storm door.
If I were rich, I’d buy a bottle for everyone who has windows. No kidding.