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 or 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, and I do have some clients where I clean their windows once or twice a month. Then you have others who like to have clean windows but don’t want to spend a lot on window cleaning. Those clients usually just call me once or twice a year. In general, however, I recommend having your windows cleaned inside and out twice a year, and just the outside every three months, since the outside usually gets dirtier then the inside. This way the windows look great year round. Believe it or not having a regular maintenence schedule is the best because this will make your windows last longer and will prevent you from having to replace them early. Dirt and hard water stains exposed to the elements can gradually damage the glass and frames. So ask your window cleaner to put you on a regular schedule. If you live in the Oklahoma City area feel free to contact me.