We have a summer home in Wyo. and need to replace the sliding glass doors that are 25 yrs. old and have served well. We have looked at Anderson, Weathershield and Sierra Pacific so far. All are rather costly, but we do need doors that will hold up to the harsh winters here. A less costly avenue would be to replace the doors only and not the frame. The frame seems to be in good condition. Does anyone know if this would be possible? Any comments on the above companies regarding quality and service.