As well as being a functional product, a bathroom mirror can play a part in your overall bathroom design. A large, well placed mirror can make a small bathroom appear bigger than it actually is - the smaller the room, the bigger the mirror required to achieve the effect.
Mirrors can also help to refelct light around the bathroom to make the most of the avilable natural light or to re-direct a ceiling mounted bathroom light. This is especially important in dark, or north facing bathrooms or rooms that have no wndow. Some mirrors also come with their own lighting - some come with wall lights, some have a backlight (making them very neat)
If ready made mirrors are just not big enough it is also possible to have mirrors cut to size - a local glass merchant or glazier should be able to help. Always make sure that the mirror youre purchasing suitable for use in bathrooms or shower rooms and will cope with steamy conditions without "silvering".