Size and design are the two most important factors when choosing couch coverings, but other factors will have an impact on the choice you make. Measure the couch carefully to ensure you purchase couch coverings that will cover the entire piece of furniture; this will prevent the couch itself from showing through, especially around the bottom of the couch. Once you have determined the size you need, think about what color, design, or style of covering you want. Try to match the covering to the overall decor of the room, and avoid colors or patterns that will clash too loudly with the other furniture.
The cost of the couch coverings you are considering will also have an impact on the choice you make. Couch coverings can vary in cost according to the size, features, and materials used to make the piece. Waterproof or water-resistant materials are likely to cost more money, though some couch coverings can be treated with chemicals that will help the material resist damage from food, moisture, and other materials. Fitted coverings will also cost more than unfitted coverings; a fitted covering is one that is designed to fit a specific size of couch, and it will wrap around each part of the couch. An unfitted cover may have extra materials in certain parts of the couch, leading to bulk or shifting material.
Think about what you want the couch covering to accomplish. Some couch coverings are designed for aesthetic appeal, and they can be used to cover a couch that is stained or otherwise damaged. Some coverings are designed to prevent dirt build up, or to prevent damage from water and food. Still others are meant to preserve the couch while it is in storage. These covers are usually less attractive than other coverings, and they may be made from materials that are not especially comfortable to sit on. The covering you choose should depend on how you intend to use it.
If you choose an unfitted covering, think about the methods by which excess material can be cinched down or otherwise tightened. Many coverings feature ties or straps that will allow you to prevent bulky material buildup. These straps should generally be out of plain view, unless they are designed with aesthetics in mind. Some decorative straps can be tied into bows to allow for aesthetic appeal as well as function, for example.