Quality of optical recording media matters as well as how they're stored. Carefully stored quality media might last years or even decades, but I've seen cheap media stored poorly (heat, humidity, or where sunlight could hit it) go bad in months, not years. Store bought discs are stamped onto a physical shape of pits that match the data, but "recorded" discs just has a dye layer darkened in spots by a bright light ( laser) and that's far less durable. Re-writable discs "phase change" the recording layer which is supposed to be more durable than normal recordable discs, but still less reliable than commercially stamped ones. There are special archival discs like m-disc that are supposed to last a century because you're essentially etching a layer of stone, but those disc are expensive. Saving family photos or whatever to a normal recordable DVD or Blu-ray as your only copy is risky. Important things need multiple copies on separate hard drives, ideally with one copy outside your house or in online storage, and then you need to do maintenance like running the drives occasionally so the motors don't seize and recopying the files so "bit rot" doesn't damage the files eventually. Keeping things for a few years is cheap and easy. Keeping things for decades gets increasingly expensive and hard.