MoSCoW

The MoSCoW rules are used by companies/businesses in their decisions to prioritize the requirements of a design since few design projects have unlimited resources. The MoSCoW rules is divided into 4 sections:

Must have
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 * fundamental requirements without which the system will be unworkable and useless, effectively the minimum usable subset. This is the purpose of a design, without this requirement the design is next to useless.
 * example, a chair must have the required seat padding for one to sit otherwise it would defeat the purpose of a chair.

Should have

 * would be essential if there were more time available to add it but the end product would be functional (usable and useful) without them
 * example, a chair that can rotate 360 degrees would be ideal because it allows for more movement for different contexts but given a circumstance the chair is still operatable without the use of the rotate.

Could have
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 * features that could help improve the design but is of lesser importance and can be easily left out of the design
 * example, a chair that includes a arm rest or a reclining back. Both add comfortable to the performance of the design project but without it the design can still function properly.

Want to have but Won't have
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 * this design can wait until a later design
 * example, a chair with leather padding. This is strictly for luxury and is not required to make a chair useful or usable.