Keeping your business clean adds to your business image. Windows is what most customers see right off the bat, among other things. Having your windows cleaned on a regular bases helps you to draw customers in!
I usually get this question a lot, but the truth is there is no right answer. It really depends on two things. First, the house, how often do the windows get dirty? If the owner has pets or small children, if the windows are in an area that gets hit by a lot of wind and rain then they probably get dirty quite often. Second, the home owner. Some people can’t stand dirty windows, not even a little. I would say at least once a year you should have your windows cleaned. It's all up to you though!
Automatic sprinklers can be great for your lawn when they are properly adjusted, but can cause damage to your windows. Over time, the water that is spraying on your windows is drying and leaving hard water deposits on your window. As the months and years go by, this buildup will "fog" your windows or hardwater deposits will be very visible. The good news is it can be remedied. The deposits can be removed by specialized chemicals that are for this, also try adjusting your sprinkler head.