We usually offer to clean the frames twice a year which is in our opinion frequent enough to keep them sufficiently clean and we charge twice the normal window clean price as in our experience it takes twice as long if done properly. On a slightly different point it would be interesting to know how the wfp guys get on with cleaning the frames using there systems as a lot of guys seem to state that they will clean the frames as well as the glass every time. We have tended to avoid this and only clean frames specifically as stated above to ensure they are done thoroughly and to avoid leaving contaminated water on the glass which you are risking if you clean the frames every time as part of the general window clean. We always clean the frames first and then go over again cleaning just the glass to ensure they are left spotless, this is the only way from three years wfp experience we have been able to guarantee good results, dont get me wrong if I thought we could clean the frames and sills every time and still have a clean brush to leave the glass spotless then that would be great and we would only charge a little extra to include this, but we have never found this to be the case, so either wfp guys who say they include the frames are either in-experienced, not cleaning the frames each time as stated and just using this as a sales gimmic when really only cleaning frames periodically, leaving glass in worse condition than they could, very lucky or we have been doing it all wrong for three years! Please enlighten us of your views???