Washing windows wouldn’t exactly classify as “maintenance”, but it is definitely as important to the appearance and enjoyment of your home as many maintenance items.  There’s also some damage that can occur when you’re washing windows- both to your home and your wallet that you want to avoid.
Windows are designed to let the light from the outside in, while keeping the air from the outside out.  They do a pretty good job of keeping wind and rain out as well, but they’re not designed to take water from all angles at any pressure level.  So be careful if you decide to use one of those glass cleaners in a bottle with a hose connection- make sure to read the directions and follow them, making sure your windows are  closed and latched tight before starting.

You can save money by simply hosing down the outside of the windows, and then using a simple sponge to wash the windows with warm water and dish washing liquid.  Wipe the glass clean with crumpled news papers, clean coffee filters, or a lint free cloth.  Wipe the sills with a clean towel, and you’re done!  No need to spend money on a specialty product or a professional window cleaner.