If you do find streaks, you'll know which side needs to be redone. Change the water often to limit or eliminate streaking. Tie a rope to your squeegee and secure it to the ladder or your belt in case you drop it. Letting the solution dry onto the window while you climb up and down to retrieve your tools could be the difference between sparkle and debacle. Try cleaning windows on cloudy, but dry, days.
Sunlight dries the solution too fast and makes streaks more likely.
Really dirty windows may need to be rinsed with the garden hose first, but be prepared to clean them immediately. Hard water stains can be stubborn. All Rights Reserved.