When it comes to choosing curtains for a 120 inch window, the width of the curtains is an important consideration. Depending on the style of window and the look you are trying to achieve, the width of your curtains will vary. For example, if you have a sliding glass door, you may want to opt for wider curtains so that they can close completely and provide privacy. However, if you have a bay window, narrower curtains may be more aesthetically pleasing. Ultimately, it is up to you to decide what look you are going for and what width of curtain will best suit your needs.