How often do you clean it? It might be after two hours of use or it might be never. For normal use of the article a means of determining when it should be cleaned is needed. Frequency of cleaning depends on many factors: cultural, personal, professional, and characteristics of the item itself. A doctor has to wear clean scrubs. However, a scarf or tie can be worn several times before it needs to be cleaned. The requirement is that determining when an article needs to be cleaned must be customizable.
How should it be cleaned? Once you've decided that an article needs to be cleaned you need to determine how it should be cleaned. Incorrect washing can be disastrous. For example, washing a cashmere sweater in the washing machine will probably ruin it. For the purposes of this case study, we're going to assume there are only a few fixed ways to clean an item (wash and dry clean) and the only customization needed is the ability to specify which of these is appropriate for a particular article of clothing. The requirement is that you need to be able to specify the cleaning method on each article of clothing.