I've done a lot of moving in my life from across the country to across the street (really, I did). Every time I move I find something old, something with a story to tell. Perhaps it's something that's been forgotten over the years or has fallen behind the bed only to be returned to the forefront of my mind and consciousness.
These little items have so much history in them and are the perfect fodder for a writer's tool bin. A character who loses her parents can find a treasure trove of family heirlooms stashed in an attic. A young man marries his high school sweetheart and they give their baby her toy box from her old nursery or a drug addicted father tries to make right by his kid by sending a team jersey for the sons birthday. The possibilities are endless.
A well rounded character needs a backstory and a history. Sometimes, and honestly most often, no one will ever learn of that backstory but you can bet that they can tell if it was never written. So write your character a backstory and give them a piece of yourself when you do it. You'll breathe life into them that way and your readers will thank you for it.