You should vacuum your upholstered furniture every week or two, to remove abrasive soil and grit that can build up and damage the fabric.
Rotate and flip your furniture cushions occasionally; this will spread out the wear and tear on them, and prolong the life of your furnishings.
Put on a rubber glove and run your hand over your upholstered furniture to remove pet hair. This will also make it easier to remove with a vacuum cleaner.
Close your blinds or curtains during the day when you are not at home. This will reduce your furniture's exposure to sunlight, which can cause the fabric to fade.
Have your upholstered furniture professionally cleaned and deodorized regularly to prevent the buildup of unpleasant odors and accumulated soil.