The answer to 'how to maintain window' is to clean and care for your windows regularly to keep them looking their best. Start by dusting the window frame and sill with a soft cloth or microfiber duster. Then, use a window cleaner and a lint-free cloth or squeegee to wipe down the glass. Be sure to clean both the interior and exterior of the windows. For hard water stains or built-up grime, you may need to use a vinegar or ammonia-based cleaner. Avoid using abrasive cleaners or scrubbing pads, as these can scratch the glass.
It's a good idea to clean your windows at least twice a year, or more often if they get very dirty. You may also want to inspect the caulking and weather stripping around the windows periodically and re-seal any cracks or gaps to prevent air leaks and water damage. If you have any windows that are difficult to reach or clean, it's best to call a professional window cleaning service to ensure they are properly maintained.