I don’t know about where you live but down here in SW Florida outdoor furniture takes a terrible beating from the weather. Two of the biggest furniture damaging culprits are sunshine and rain.
Being under cover makes little difference when scorching sun beams shine through the open windows or screened partitions. Seat cushions, arm pillows, and really anything made of fabric will fade dramatically. The other factor associated with the sun is the heat. Oh my, the heat index is commonly around 105 degrees in the summer months. This intense heat really messes with fabrics, especially foam backed fabrics. Sewing your own patio seat cushions can be a real task for a Florida DIY newbie. Many fabrics that are considered outdoor fabrics elsewhere just will not hold up down here. Our furniture is hand braided resin wicker fiber and is reasonably resistant. Using individual UV resistant store bought seat cushions that are stored indoors has been cost effective and keeps out outdoor patio looking new.
As for the rain, never mind trying to keep patio furniture dry without the patio being completely enclosed and includes vinyl windows. The driving rainstorms are plentiful in the summer. With a true tropical nature, the driving rain blows sideways often times leaving no way to keep a patio dry. Owning expensive grills, outdoor cookers, and other patio furniture without patio furniture covers is a huge mistake. Without protection, be prepared to replace those outdoor items rather quickly, I’m just sayin’.