I tried several window cleaning services before I found Sparkling Windows. The major difference in the quality of their work is, simply, that they leave no streaks. My windows are crystal clear when they finish. I used to have my windows cleaned twice a year. Sparkling Windows did such a great job last Spring that I was able to go a whole year before they needed washing. Their price is comparable to others I have used with far better results and they do the job quickly and efficiently.