New windows require a certain level of skill to insure that the fit, operation and finish are perfect. Vinyl replacement windows present extra challenges. Removing an existing window can be a huge task if you don't have the right tools. Existing (and even new houses!) houses can have out of square window openings. The restoration of interior plaster and trim surfaces requires significant coordination and special tools. Exterior caulking, interior insulation installation, etc. all must be accomplished perfectly or you will have a mess - and a drafty window - on your hands.