The arms of your sofa seem to wear out faster then any other part of your sofa. The second is the sofa cushions. The arms wear out fastest because they get the most wear and tear from people’s arms sitting and rubbing on them. It is a good idea to keep them covered to help reduce the wear and tear.
The sofa cushions are hard to cover unless you cover the whole sofa. Since you can not cover the cushions as easily as you can the sofa arm rests you will need to clean them more then the rest of the sofa.
Some sofa cushions are pretty sturdy and if you are not too hard on them all you need to do is give them a good vacuuming once a week. That should keep them looking good for a long time.
If you are hard on your sofa cushions for example you let your pets up on the sofa then you will need to do more to keep them clean. You should still vacuum the cushions once a week or maybe even more to keep them clean. You may need to wash them occasionally too. Some cloth sofas have zippers on the back of the cushions. Usually you can zip them off and take the covers off of the cushions. Then you can wash them in your washing machine on a cool cycle. Make sure your fabric is a washable type before you do this.
If you have a leather sofa or one that should not be washed in a washing machine you will need to take your cushions to a dry cleaner. The dry cleaner will clean your cushions properly.
You may drop something on your sofa cushions and leave a spot. Many spots can be cleaned off with a clean moist cloth if the spot is not too obstinate and hard to clean off. For harder to clean spots you can find several good furniture spot cleaners on the market. These cleaners are made especially for spot cleaning your furniture spots. You can also get a furniture cleaning machine like a carpet cleaning machine to help you wash your sofa and keep it clean.
If you use your furniture it will get dirty no matter if you eat and drink on it or not. Every so often you can expect to have to clean your sofa and other furniture.